Guide to the Secure Configuration of Red Hat Enterprise Linux CoreOS 4

with profile DRAFT - ANSSI-BP-028 (high)
This profile contains configurations that align to ANSSI-BP-028 at the high hardening level. ANSSI is the French National Information Security Agency, and stands for Agence nationale de la sécurité des systèmes d'information. ANSSI-BP-028 is a configuration recommendation for GNU/Linux systems. A copy of the ANSSI-BP-028 can be found at the ANSSI website: https://www.ssi.gouv.fr/administration/guide/recommandations-de-securite-relatives-a-un-systeme-gnulinux/
This guide presents a catalog of security-relevant configuration settings for Red Hat Enterprise Linux CoreOS 4. It is a rendering of content structured in the eXtensible Configuration Checklist Description Format (XCCDF) in order to support security automation. The SCAP content is is available in the scap-security-guide package which is developed at https://www.open-scap.org/security-policies/scap-security-guide.

Providing system administrators with such guidance informs them how to securely configure systems under their control in a variety of network roles. Policy makers and baseline creators can use this catalog of settings, with its associated references to higher-level security control catalogs, in order to assist them in security baseline creation. This guide is a catalog, not a checklist, and satisfaction of every item is not likely to be possible or sensible in many operational scenarios. However, the XCCDF format enables granular selection and adjustment of settings, and their association with OVAL and OCIL content provides an automated checking capability. Transformations of this document, and its associated automated checking content, are capable of providing baselines that meet a diverse set of policy objectives. Some example XCCDF Profiles, which are selections of items that form checklists and can be used as baselines, are available with this guide. They can be processed, in an automated fashion, with tools that support the Security Content Automation Protocol (SCAP). The DISA STIG, which provides required settings for US Department of Defense systems, is one example of a baseline created from this guidance.
Do not attempt to implement any of the settings in this guide without first testing them in a non-operational environment. The creators of this guidance assume no responsibility whatsoever for its use by other parties, and makes no guarantees, expressed or implied, about its quality, reliability, or any other characteristic.
Profile TitleDRAFT - ANSSI-BP-028 (high)
Profile IDxccdf_org.ssgproject.content_profile_anssi_bp28_high

Revision History

Current version: 0.1.70

  • draft (as of 2023-12-07)

Platforms

  • cpe:/o:redhat:enterprise_linux_coreos:4

Table of Contents

  1. System Settings
    1. Installing and Maintaining Software
    2. Account and Access Control
    3. System Accounting with auditd
    4. GRUB2 bootloader configuration
    5. Kernel Configuration
    6. Configure Syslog
    7. Network Configuration and Firewalls
    8. File Permissions and Masks
    9. SELinux
  2. Services
    1. Mail Server Software
    2. Network Time Protocol
    3. SSH Server

Checklist

contains 200 rules

System Settings   [ref]group

Contains rules that check correct system settings.

contains 191 rules

Installing and Maintaining Software   [ref]group

The following sections contain information on security-relevant choices during the initial operating system installation process and the setup of software updates.

contains 20 rules

System and Software Integrity   [ref]group

System and software integrity can be gained by installing antivirus, increasing system encryption strength with FIPS, verifying installed software, enabling SELinux, installing an Intrusion Prevention System, etc. However, installing or enabling integrity checking tools cannot prevent intrusions, but they can detect that an intrusion may have occurred. Requirements for integrity checking may be highly dependent on the environment in which the system will be used. Snapshot-based approaches such as AIDE may induce considerable overhead in the presence of frequent software updates.

contains 3 rules

Software Integrity Checking   [ref]group

Both the AIDE (Advanced Intrusion Detection Environment) software and the RPM package management system provide mechanisms for verifying the integrity of installed software. AIDE uses snapshots of file metadata (such as hashes) and compares these to current system files in order to detect changes.

The RPM package management system can conduct integrity checks by comparing information in its metadata database with files installed on the system.

contains 2 rules

Verify Integrity with AIDE   [ref]group

AIDE conducts integrity checks by comparing information about files with previously-gathered information. Ideally, the AIDE database is created immediately after initial system configuration, and then again after any software update. AIDE is highly configurable, with further configuration information located in /usr/share/doc/aide-VERSION.

contains 2 rules

Install AIDE   [ref]rule

The aide package can be installed with the following command:

Rationale:

The AIDE package must be installed if it is to be available for integrity checking.

Severity:  medium

Build and Test AIDE Database   [ref]rule

Run the following command to generate a new database:

$ sudo /usr/sbin/aide --init
By default, the database will be written to the file /var/lib/aide/aide.db.new.gz. Storing the database, the configuration file /etc/aide.conf, and the binary /usr/sbin/aide (or hashes of these files), in a secure location (such as on read-only media) provides additional assurance about their integrity. The newly-generated database can be installed as follows:
$ sudo cp /var/lib/aide/aide.db.new.gz /var/lib/aide/aide.db.gz
To initiate a manual check, run the following command:
$ sudo /usr/sbin/aide --check
If this check produces any unexpected output, investigate.

Rationale:

For AIDE to be effective, an initial database of "known-good" information about files must be captured and it should be able to be verified against the installed files.

Severity:  medium

Federal Information Processing Standard (FIPS)   [ref]group

The Federal Information Processing Standard (FIPS) is a computer security standard which is developed by the U.S. Government and industry working groups to validate the quality of cryptographic modules. The FIPS standard provides four security levels to ensure adequate coverage of different industries, implementation of cryptographic modules, and organizational sizes and requirements.

FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets industry and government requirements. For government systems, this allows Security Levels 1, 2, 3, or 4 for use on Red Hat Enterprise Linux CoreOS 4.

See http://csrc.nist.gov/publications/PubsFIPS.html for more information.

contains 1 rule

Install the dracut-fips-aesni Package   [ref]rule

To enable FIPS on system that support the Advanced Encryption Standard (AES) or New Instructions (AES-NI) engine, the system requires that the dracut-fips-aesni package be installed. The dracut-fips-aesni package can be installed with the following command:

Warning:  The system needs to be rebooted for these changes to take effect.
Warning:  System Crypto Modules must be provided by a vendor that undergoes FIPS-140 certifications. FIPS-140 is applicable to all Federal agencies that use cryptographic-based security systems to protect sensitive information in computer and telecommunication systems (including voice systems) as defined in Section 5131 of the Information Technology Management Reform Act of 1996, Public Law 104-106. This standard shall be used in designing and implementing cryptographic modules that Federal departments and agencies operate or are operated for them under contract. See https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.140-2.pdf To meet this, the system has to have cryptographic software provided by a vendor that has undergone this certification. This means providing documentation, test results, design information, and independent third party review by an accredited lab. While open source software is capable of meeting this, it does not meet FIPS-140 unless the vendor submits to this process.
Rationale:

Use of weak or untested encryption algorithms undermines the purposes of utilizing encryption to protect data. The operating system must implement cryptographic modules adhering to the higher standards approved by the federal government since this provides assurance they have been tested and validated.

Severity:  medium

Disk Partitioning   [ref]group

To ensure separation and protection of data, there are top-level system directories which should be placed on their own physical partition or logical volume. The installer's default partitioning scheme creates separate logical volumes for /, /boot, and swap.

  • If starting with any of the default layouts, check the box to \"Review and modify partitioning.\" This allows for the easy creation of additional logical volumes inside the volume group already created, though it may require making /'s logical volume smaller to create space. In general, using logical volumes is preferable to using partitions because they can be more easily adjusted later.
  • If creating a custom layout, create the partitions mentioned in the previous paragraph (which the installer will require anyway), as well as separate ones described in the following sections.
If a system has already been installed, and the default partitioning scheme was used, it is possible but nontrivial to modify it to create separate logical volumes for the directories listed above. The Logical Volume Manager (LVM) makes this possible. See the LVM HOWTO at http://tldp.org/HOWTO/LVM-HOWTO/ for more detailed information on LVM.

contains 7 rules

Ensure /home Located On Separate Partition   [ref]rule

If user home directories will be stored locally, create a separate partition for /home at installation time (or migrate it later using LVM). If /home will be mounted from another system such as an NFS server, then creating a separate partition is not necessary at installation time, and the mountpoint can instead be configured later.

Rationale:

Ensuring that /home is mounted on its own partition enables the setting of more restrictive mount options, and also helps ensure that users cannot trivially fill partitions used for log or audit data storage.

Severity:  low

Ensure /srv Located On Separate Partition   [ref]rule

If a file server (FTP, TFTP...) is hosted locally, create a separate partition for /srv at installation time (or migrate it later using LVM). If /srv will be mounted from another system such as an NFS server, then creating a separate partition is not necessary at installation time, and the mountpoint can instead be configured later.

Rationale:

Srv deserves files for local network file server such as FTP. Ensuring that /srv is mounted on its own partition enables the setting of more restrictive mount options, and also helps ensure that users cannot trivially fill partitions used for log or audit data storage.

Severity:  unknown

References:  BP28(R12)

Ensure /tmp Located On Separate Partition   [ref]rule

The /tmp directory is a world-writable directory used for temporary file storage. Ensure it has its own partition or logical volume at installation time, or migrate it using LVM.

Rationale:

The /tmp partition is used as temporary storage by many programs. Placing /tmp in its own partition enables the setting of more restrictive mount options, which can help protect programs which use it.

Severity:  low

Ensure /var Located On Separate Partition   [ref]rule

The /var directory is used by daemons and other system services to store frequently-changing data. Ensure that /var has its own partition or logical volume at installation time, or migrate it using LVM.

Rationale:

Ensuring that /var is mounted on its own partition enables the setting of more restrictive mount options. This helps protect system services such as daemons or other programs which use it. It is not uncommon for the /var directory to contain world-writable directories installed by other software packages.

Severity:  low

Ensure /var/log Located On Separate Partition   [ref]rule

System logs are stored in the /var/log directory.

Partitioning Red Hat CoreOS is a Day 1 operation and cannot be changed afterwards. For documentation on how to add a MachineConfig manifest that specifies a separate /var/log partition, follow: https://docs.openshift.com/container-platform/latest/installing/installing_platform_agnostic/installing-platform-agnostic.html#installation-user-infra-machines-advanced_disk_installing-platform-agnostic

Note that the Red Hat OpenShift documentation often references a block device, such as /dev/vda. The name of the available block devices depends on the underlying infrastructure (bare metal vs cloud), and often the specific instance type. For example in AWS, some instance types have NVMe drives (/dev/nvme*), others use /dev/xvda*. You will need to look for relevant documentation for your infrastructure around this. In many cases, the simplest thing is to boot a single machine with an Ignition configuration that just gives you SSH access, and inspect the block devices via e.g. the lsblk command. For physical hardware, a good best practice is to reference devices via the /dev/disk/by-id/ or /dev/disk/by-path links.

Rationale:

Placing /var/log in its own partition enables better separation between log files and other files in /var/.

Severity:  low

Ensure /var/log/audit Located On Separate Partition   [ref]rule

Audit logs are stored in the /var/log/audit directory.

Partitioning Red Hat CoreOS is a Day 1 operation and cannot be changed afterwards. For documentation on how to add a MachineConfig manifest that specifies a separate /var/log/audit partition, follow: https://docs.openshift.com/container-platform/latest/installing/installing_platform_agnostic/installing-platform-agnostic.html#installation-user-infra-machines-advanced_disk_installing-platform-agnostic

Note that the Red Hat OpenShift documentation often references a block device, such as /dev/vda. The name of the available block devices depends on the underlying infrastructure (bare metal vs cloud), and often the specific instance type. For example in AWS, some instance types have NVMe drives (/dev/nvme*), others use /dev/xvda*. You will need to look for relevant documentation for your infrastructure around this. In many cases, the simplest thing is to boot a single machine with an Ignition configuration that just gives you SSH access, and inspect the block devices via e.g. the lsblk command. For physical hardware, a good best practice is to reference devices via the /dev/disk/by-id/ or /dev/disk/by-path links.

Make absolutely certain that it is large enough to store all audit logs that will be created by the auditing daemon.

Rationale:

Placing /var/log/audit in its own partition enables better separation between audit files and other files, and helps ensure that auditing cannot be halted due to the partition running out of space.

Severity:  low

Ensure /var/tmp Located On Separate Partition   [ref]rule

The /var/tmp directory is a world-writable directory used for temporary file storage. Ensure it has its own partition or logical volume at installation time, or migrate it using LVM.

Rationale:

The /var/tmp partition is used as temporary storage by many programs. Placing /var/tmp in its own partition enables the setting of more restrictive mount options, which can help protect programs which use it.

Severity:  medium

Identifiers:  CCE-82734-5

References:  BP28(R12), SRG-OS-000480-GPOS-00227

Sudo   [ref]group

Sudo, which stands for "su 'do'", provides the ability to delegate authority to certain users, groups of users, or system administrators. When configured for system users and/or groups, Sudo can allow a user or group to execute privileged commands that normally only root is allowed to execute.

For more information on Sudo and addition Sudo configuration options, see https://www.sudo.ws.

contains 8 rules

Install sudo Package   [ref]rule

The sudo package can be installed with the following command:

Rationale:

sudo is a program designed to allow a system administrator to give limited root privileges to users and log root activity. The basic philosophy is to give as few privileges as possible but still allow system users to get their work done.

Severity:  medium

Identifiers:  CCE-82523-2

References:  BP28(R19), 1382, 1384, 1386, CM-6(a), FMT_MOF_EXT.1, 10.2.1.5, SRG-OS-000324-GPOS-00125

Ensure Privileged Escalated Commands Cannot Execute Other Commands - sudo NOEXEC   [ref]rule

The sudo NOEXEC tag, when specified, prevents user executed commands from executing other commands, like a shell for example. This should be enabled by making sure that the NOEXEC tag exists in /etc/sudoers configuration file or any sudo configuration snippets in /etc/sudoers.d/.

Rationale:

Restricting the capability of sudo allowed commands to execute sub-commands prevents users from running programs with privileges they wouldn't have otherwise.

Severity:  high

References:  BP28(R58)

Ensure Only Users Logged In To Real tty Can Execute Sudo - sudo requiretty   [ref]rule

The sudo requiretty tag, when specified, will only execute sudo commands from users logged in to a real tty. This should be enabled by making sure that the requiretty tag exists in /etc/sudoers configuration file or any sudo configuration snippets in /etc/sudoers.d/.

Rationale:

Restricting the use cases in which a user is allowed to execute sudo commands reduces the attack surface.

Severity:  medium

References:  BP28(R58)

Ensure Only Users Logged In To Real tty Can Execute Sudo - sudo use_pty   [ref]rule

The sudo use_pty tag, when specified, will only execute sudo commands from users logged in to a real tty. This should be enabled by making sure that the use_pty tag exists in /etc/sudoers configuration file or any sudo configuration snippets in /etc/sudoers.d/.

Rationale:

Requiring that sudo commands be run in a pseudo-terminal can prevent an attacker from retaining access to the user's terminal after the main program has finished executing.

Severity:  medium

References:  BP28(R58), Req-10.2.5, 10.2.1.5

Ensure Users Re-Authenticate for Privilege Escalation - sudo !authenticate   [ref]rule

The sudo !authenticate option, when specified, allows a user to execute commands using sudo without having to authenticate. This should be disabled by making sure that the !authenticate option does not exist in /etc/sudoers configuration file or any sudo configuration snippets in /etc/sudoers.d/.

Rationale:

Without re-authentication, users may access resources or perform tasks for which they do not have authorization.

When operating systems provide the capability to escalate a functional capability, it is critical that the user re-authenticate.

Severity:  medium

Ensure Users Re-Authenticate for Privilege Escalation - sudo NOPASSWD   [ref]rule

The sudo NOPASSWD tag, when specified, allows a user to execute commands using sudo without having to authenticate. This should be disabled by making sure that the NOPASSWD tag does not exist in /etc/sudoers configuration file or any sudo configuration snippets in /etc/sudoers.d/.

Rationale:

Without re-authentication, users may access resources or perform tasks for which they do not have authorization.

When operating systems provide the capability to escalate a functional capability, it is critical that the user re-authenticate.

Severity:  medium

Explicit arguments in sudo specifications   [ref]rule

All commands in the sudoers file must strictly specify the arguments allowed to be used for a given user. If the command is supposed to be executed only without arguments, pass "" as an argument in the corresponding user specification.

Warning:  This rule doesn't come with a remediation, as absence of arguments in the user spec doesn't mean that the command is intended to be executed with no arguments.
Warning:  The rule can produce false findings when an argument contains a comma - sudoers syntax allows comma escaping using backslash, but the check doesn't support that. For example, root ALL=(ALL) echo 1\,2 allows root to execute echo 1,2, but the check would interpret it as two commands echo 1\ and 2.
Rationale:

Any argument can modify quite significantly the behavior of a program, whether regarding the realized operation (read, write, delete, etc.) or accessed resources (path in a file system tree). To avoid any possibility of misuse of a command by a user, the ambiguities must be removed at the level of its specification. For example, on some systems, the kernel messages are only accessible by root. If a user nevertheless must have the privileges to read them, the argument of the dmesg command has to be restricted in order to prevent the user from flushing the buffer through the -c option:

user ALL = dmesg ""

Severity:  medium

References:  BP28(R63)

Don't define allowed commands in sudoers by means of exclusion   [ref]rule

Policies applied by sudo through the sudoers file should not involve negation. Each user specification in the sudoers file contains a comma-delimited list of command specifications. The definition can make use glob patterns, as well as of negations. Indirect definition of those commands by means of exclusion of a set of commands is trivial to bypass, so it is not allowed to use such constructs.

Warning:  This rule doesn't come with a remediation, as negations indicate design issues with the sudoers user specifications design. Just removing negations doesn't increase the security - you typically have to rethink the definition of allowed commands to fix the issue.
Rationale:

Specifying access right using negation is inefficient and can be easily circumvented. For example, it is expected that a specification like

# To avoid absolutely , this rule can be easily circumvented!
user ALL = ALL ,!/ bin/sh
prevents the execution of the shell but that’s not the case: just copy the binary /bin/sh to a different name to make it executable again through the rule keyword ALL.

Severity:  medium

References:  BP28(R61)

Updating Software   [ref]group

The command line tool is used to install and update software packages. The system also provides a graphical software update tool in the System menu, in the Administration submenu, called Software Update.

Red Hat Enterprise Linux CoreOS 4 systems contain an installed software catalog called the RPM database, which records metadata of installed packages. Consistently using or the graphical Software Update for all software installation allows for insight into the current inventory of installed software on the system.

contains 1 rule

Ensure Red Hat GPG Key Installed   [ref]rule

To ensure the system can cryptographically verify base software packages come from Red Hat (and to connect to the Red Hat Network to receive them), the Red Hat GPG key must properly be installed. To install the Red Hat GPG key, run:

$ sudo subscription-manager register
If the system is not connected to the Internet or an RHN Satellite, then install the Red Hat GPG key from trusted media such as the Red Hat installation CD-ROM or DVD. Assuming the disc is mounted in /media/cdrom, use the following command as the root user to import it into the keyring:
$ sudo rpm --import /media/cdrom/RPM-GPG-KEY
Alternatively, the key may be pre-loaded during the RHEL installation. In such cases, the key can be installed by running the following command:
sudo rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release

Rationale:

Changes to software components can have significant effects on the overall security of the operating system. This requirement ensures the software has not been tampered with and that it has been provided by a trusted vendor. The Red Hat GPG key is necessary to cryptographically verify packages are from Red Hat.

Severity:  high

Prefer to use a 64-bit Operating System when supported   [ref]rule

Prefer installation of 64-bit operating systems when the CPU supports it.

Warning:  There is no remediation besides installing a 64-bit operating system.
Rationale:

Use of a 64-bit operating system offers a few advantages, like a larger address space range for Address Space Layout Randomization (ASLR) and systematic presence of No eXecute and Execute Disable (NX/XD) protection bits.

Severity:  medium

References:  BP28(R10)

Account and Access Control   [ref]group

In traditional Unix security, if an attacker gains shell access to a certain login account, they can perform any action or access any file to which that account has access. Therefore, making it more difficult for unauthorized people to gain shell access to accounts, particularly to privileged accounts, is a necessary part of securing a system. This section introduces mechanisms for restricting access to accounts under Red Hat Enterprise Linux CoreOS 4.

contains 9 rules

Protect Accounts by Restricting Password-Based Login   [ref]group

Conventionally, Unix shell accounts are accessed by providing a username and password to a login program, which tests these values for correctness using the /etc/passwd and /etc/shadow files. Password-based login is vulnerable to guessing of weak passwords, and to sniffing and man-in-the-middle attacks against passwords entered over a network or at an insecure console. Therefore, mechanisms for accessing accounts by entering usernames and passwords should be restricted to those which are operationally necessary.

contains 3 rules

Set Password Expiration Parameters   [ref]group

The file /etc/login.defs controls several password-related settings. Programs such as passwd, su, and login consult /etc/login.defs to determine behavior with regard to password aging, expiration warnings, and length. See the man page login.defs(5) for more information.

Users should be forced to change their passwords, in order to decrease the utility of compromised passwords. However, the need to change passwords often should be balanced against the risk that users will reuse or write down passwords if forced to change them too often. Forcing password changes every 90-360 days, depending on the environment, is recommended. Set the appropriate value as PASS_MAX_DAYS and apply it to existing accounts with the -M flag.

The PASS_MIN_DAYS (-m) setting prevents password changes for 7 days after the first change, to discourage password cycling. If you use this setting, train users to contact an administrator for an emergency password change in case a new password becomes compromised. The PASS_WARN_AGE (-W) setting gives users 7 days of warnings at login time that their passwords are about to expire.

For example, for each existing human user USER, expiration parameters could be adjusted to a 180 day maximum password age, 7 day minimum password age, and 7 day warning period with the following command:

$ sudo chage -M 180 -m 7 -W 7 USER

contains 2 rules

Restrict Root Logins   [ref]group

Direct root logins should be allowed only for emergency use. In normal situations, the administrator should access the system via a unique unprivileged account, and then use su or sudo to execute privileged commands. Discouraging administrators from accessing the root account directly ensures an audit trail in organizations with multiple administrators. Locking down the channels through which root can connect directly also reduces opportunities for password-guessing against the root account. The login program uses the file /etc/securetty to determine which interfaces should allow root logins. The virtual devices /dev/console and /dev/tty* represent the system consoles (accessible via the Ctrl-Alt-F1 through Ctrl-Alt-F6 keyboard sequences on a default installation). The default securetty file also contains /dev/vc/*. These are likely to be deprecated in most environments, but may be retained for compatibility. Root should also be prohibited from connecting via network protocols. Other sections of this document include guidance describing how to prevent root from logging in via SSH.

contains 1 rule

Direct root Logins Not Allowed   [ref]rule

To further limit access to the root account, administrators can disable root logins at the console by editing the /etc/securetty file. This file lists all devices the root user is allowed to login to. If the file does not exist at all, the root user can login through any communication device on the system, whether via the console or via a raw network interface. This is dangerous as user can login to the system as root via Telnet, which sends the password in plain text over the network. By default, Red Hat Enterprise Linux CoreOS 4's /etc/securetty file only allows the root user to login at the console physically attached to the system. To prevent root from logging in, remove the contents of this file. To prevent direct root logins, remove the contents of this file by typing the following command:

$ sudo echo > /etc/securetty

Warning:  This rule only checks the /etc/securetty file existence and its content. If you need to restrict user access using the /etc/securetty file, make sure the pam_securetty.so PAM module is properly enabled in relevant PAM files.
Rationale:

Disabling direct root logins ensures proper accountability and multifactor authentication to privileged accounts. Users will first login, then escalate to privileged (root) access via su / sudo. This is required for FISMA Low and FISMA Moderate systems.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,
        mode: 0600
        path: /etc/securetty
        overwrite: true

Secure Session Configuration Files for Login Accounts   [ref]group

When a user logs into a Unix account, the system configures the user's session by reading a number of files. Many of these files are located in the user's home directory, and may have weak permissions as a result of user error or misconfiguration. If an attacker can modify or even read certain types of account configuration information, they can often gain full access to the affected user's account. Therefore, it is important to test and correct configuration file permissions for interactive accounts, particularly those of privileged users such as root or system administrators.

contains 6 rules

Ensure that Users Have Sensible Umask Values   [ref]group

The umask setting controls the default permissions for the creation of new files. With a default umask setting of 077, files and directories created by users will not be readable by any other user on the system. Users who wish to make specific files group- or world-readable can accomplish this by using the chmod command. Additionally, users can make all their files readable to their group by default by setting a umask of 027 in their shell configuration files. If default per-user groups exist (that is, if every user has a default group whose name is the same as that user's username and whose only member is the user), then it may even be safe for users to select a umask of 007, making it very easy to intentionally share files with groups of which the user is a member.

contains 3 rules

Ensure the Default Bash Umask is Set Correctly   [ref]rule

To ensure the default umask for users of the Bash shell is set properly, add or correct the umask setting in /etc/bashrc to read as follows:

umask 077

Rationale:

The umask value influences the permissions assigned to files when they are created. A misconfigured umask value could result in files with excessive permissions that can be read or written to by unauthorized users.

Severity:  medium

Remediation script:   (show)

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,%23%20/etc/bashrc%0A%0A%23%20System%20wide%20functions%20and%20aliases%0A%23%20Environment%20stuff%20goes%20in%20/etc/profile%0A%0A%23%20It%27s%20NOT%20a%20good%20idea%20to%20change%20this%20file%20unless%20you%20know%20what%20you%0A%23%20are%20doing.%20It%27s%20much%20better%20to%20create%20a%20custom.sh%20shell%20script%20in%0A%23%20/etc/profile.d/%20to%20make%20custom%20changes%20to%20your%20environment%2C%20as%20this%0A%23%20will%20prevent%20the%20need%20for%20merging%20in%20future%20updates.%0A%0A%23%20Prevent%20doublesourcing%0Aif%20%5B%20-z%20%22%24BASHRCSOURCED%22%20%5D%3B%20then%0A%20%20BASHRCSOURCED%3D%22Y%22%0A%0A%20%20%23%20are%20we%20an%20interactive%20shell%3F%0A%20%20if%20%5B%20%22%24PS1%22%20%5D%3B%20then%0A%20%20%20%20if%20%5B%20-z%20%22%24PROMPT_COMMAND%22%20%5D%3B%20then%0A%20%20%20%20%20%20case%20%24TERM%20in%0A%20%20%20%20%20%20xterm%2A%7Cvte%2A%29%0A%20%20%20%20%20%20%20%20if%20%5B%20-e%20/etc/sysconfig/bash-prompt-xterm%20%5D%3B%20then%0A%20%20%20%20%20%20%20%20%20%20%20%20PROMPT_COMMAND%3D/etc/sysconfig/bash-prompt-xterm%0A%20%20%20%20%20%20%20%20elif%20%5B%20%22%24%7BVTE_VERSION%3A-0%7D%22%20-ge%203405%20%5D%3B%20then%0A%20%20%20%20%20%20%20%20%20%20%20%20PROMPT_COMMAND%3D%22__vte_prompt_command%22%0A%20%20%20%20%20%20%20%20else%0A%20%20%20%20%20%20%20%20%20%20%20%20PROMPT_COMMAND%3D%27printf%20%22%5C033%5D0%3B%25s%40%25s%3A%25s%5C007%22%20%22%24%7BUSER%7D%22%20%22%24%7BHOSTNAME%25%25.%2A%7D%22%20%22%24%7BPWD/%23%24HOME/%5C~%7D%22%27%0A%20%20%20%20%20%20%20%20fi%0A%20%20%20%20%20%20%20%20%3B%3B%0A%20%20%20%20%20%20screen%2A%29%0A%20%20%20%20%20%20%20%20if%20%5B%20-e%20/etc/sysconfig/bash-prompt-screen%20%5D%3B%20then%0A%20%20%20%20%20%20%20%20%20%20%20%20PROMPT_COMMAND%3D/etc/sysconfig/bash-prompt-screen%0A%20%20%20%20%20%20%20%20else%0A%20%20%20%20%20%20%20%20%20%20%20%20PROMPT_COMMAND%3D%27printf%20%22%5C033k%25s%40%25s%3A%25s%5C033%5C%5C%22%20%22%24%7BUSER%7D%22%20%22%24%7BHOSTNAME%25%25.%2A%7D%22%20%22%24%7BPWD/%23%24HOME/%5C~%7D%22%27%0A%20%20%20%20%20%20%20%20fi%0A%20%20%20%20%20%20%20%20%3B%3B%0A%20%20%20%20%20%20%2A%29%0A%20%20%20%20%20%20%20%20%5B%20-e%20/etc/sysconfig/bash-prompt-default%20%5D%20%26%26%20PROMPT_COMMAND%3D/etc/sysconfig/bash-prompt-default%0A%20%20%20%20%20%20%20%20%3B%3B%0A%20%20%20%20%20%20esac%0A%20%20%20%20fi%0A%20%20%20%20%23%20Turn%20on%20parallel%20history%0A%20%20%20%20shopt%20-s%20histappend%0A%20%20%20%20history%20-a%0A%20%20%20%20%23%20Turn%20on%20checkwinsize%0A%20%20%20%20shopt%20-s%20checkwinsize%0A%20%20%20%20%5B%20%22%24PS1%22%20%3D%20%22%5C%5Cs-%5C%5Cv%5C%5C%5C%24%20%22%20%5D%20%26%26%20PS1%3D%22%5B%5Cu%40%5Ch%20%5CW%5D%5C%5C%24%20%22%0A%20%20%20%20%23%20You%20might%20want%20to%20have%20e.g.%20tty%20in%20prompt%20%28e.g.%20more%20virtual%20machines%29%0A%20%20%20%20%23%20and%20console%20windows%0A%20%20%20%20%23%20If%20you%20want%20to%20do%20so%2C%20just%20add%20e.g.%0A%20%20%20%20%23%20if%20%5B%20%22%24PS1%22%20%5D%3B%20then%0A%20%20%20%20%23%20%20%20PS1%3D%22%5B%5Cu%40%5Ch%3A%5Cl%20%5CW%5D%5C%5C%24%20%22%0A%20%20%20%20%23%20fi%0A%20%20%20%20%23%20to%20your%20custom%20modification%20shell%20script%20in%20/etc/profile.d/%20directory%0A%20%20fi%0A%0A%20%20if%20%21%20shopt%20-q%20login_shell%20%3B%20then%20%23%20We%27re%20not%20a%20login%20shell%0A%20%20%20%20%23%20Need%20to%20redefine%20pathmunge%2C%20it%20gets%20undefined%20at%20the%20end%20of%20/etc/profile%0A%20%20%20%20pathmunge%20%28%29%20%7B%0A%20%20%20%20%20%20%20%20case%20%22%3A%24%7BPATH%7D%3A%22%20in%0A%20%20%20%20%20%20%20%20%20%20%20%20%2A%3A%22%241%22%3A%2A%29%0A%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%3B%3B%0A%20%20%20%20%20%20%20%20%20%20%20%20%2A%29%0A%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20if%20%5B%20%22%242%22%20%3D%20%22after%22%20%5D%20%3B%20then%0A%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20PATH%3D%24PATH%3A%241%0A%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20else%0A%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20PATH%3D%241%3A%24PATH%0A%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20fi%0A%20%20%20%20%20%20%20%20esac%0A%20%20%20%20%7D%0A%0A%20%20%20%20%23%20By%20default%2C%20we%20want%20umask%20to%20get%20set.%20This%20sets%20it%20for%20non-login%20shell.%0A%20%20%20%20%23%20Current%20threshold%20for%20system%20reserved%20uid/gids%20is%20200%0A%20%20%20%20%23%20You%20could%20check%20uidgid%20reservation%20validity%20in%0A%20%20%20%20%23%20/usr/share/doc/setup-%2A/uidgid%20file%0A%20%20%20%20if%20%5B%20%24UID%20-gt%20199%20%5D%20%26%26%20%5B%20%22%60id%20-gn%60%22%20%3D%20%22%60id%20-un%60%22%20%5D%3B%20then%0A%20%20%20%20%20%20%20umask%20027%0A%20%20%20%20else%0A%20%20%20%20%20%20%20umask%20027%0A%20%20%20%20fi%0A%0A%20%20%20%20SHELL%3D/bin/bash%0A%20%20%20%20%23%20Only%20display%20echos%20from%20profile.d%20scripts%20if%20we%20are%20no%20login%20shell%0A%20%20%20%20%23%20and%20interactive%20-%20otherwise%20just%20process%20them%20to%20set%20envvars%0A%20%20%20%20for%20i%20in%20/etc/profile.d/%2A.sh%3B%20do%0A%20%20%20%20%20%20%20%20if%20%5B%20-r%20%22%24i%22%20%5D%3B%20then%0A%20%20%20%20%20%20%20%20%20%20%20%20if%20%5B%20%22%24PS1%22%20%5D%3B%20then%0A%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20.%20%22%24i%22%0A%20%20%20%20%20%20%20%20%20%20%20%20else%0A%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20.%20%22%24i%22%20%3E/dev/null%0A%20%20%20%20%20%20%20%20%20%20%20%20fi%0A%20%20%20%20%20%20%20%20fi%0A%20%20%20%20done%0A%0A%20%20%20%20unset%20i%0A%20%20%20%20unset%20-f%20pathmunge%0A%20%20fi%0A%0Afi%0A%23%20vim%3Ats%3D4%3Asw%3D4%0A%0A%0A
        mode: 0644
        path: /etc/bashrc
        overwrite: true

Ensure the Default Umask is Set Correctly in /etc/profile   [ref]rule

To ensure the default umask controlled by /etc/profile is set properly, add or correct the umask setting in /etc/profile to read as follows:

umask 077
Note that /etc/profile also reads scrips within /etc/profile.d directory. These scripts are also valid files to set umask value. Therefore, they should also be considered during the check and properly remediated, if necessary.

Rationale:

The umask value influences the permissions assigned to files when they are created. A misconfigured umask value could result in files with excessive permissions that can be read or written to by unauthorized users.

Severity:  medium

Remediation script:   (show)

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,%23%20/etc/profile%0A%0A%23%20System%20wide%20environment%20and%20startup%20programs%2C%20for%20login%20setup%0A%23%20Functions%20and%20aliases%20go%20in%20/etc/bashrc%0A%0A%23%20It%27s%20NOT%20a%20good%20idea%20to%20change%20this%20file%20unless%20you%20know%20what%20you%0A%23%20are%20doing.%20It%27s%20much%20better%20to%20create%20a%20custom.sh%20shell%20script%20in%0A%23%20/etc/profile.d/%20to%20make%20custom%20changes%20to%20your%20environment%2C%20as%20this%0A%23%20will%20prevent%20the%20need%20for%20merging%20in%20future%20updates.%0A%0Apathmunge%20%28%29%20%7B%0A%20%20%20%20case%20%22%3A%24%7BPATH%7D%3A%22%20in%0A%20%20%20%20%20%20%20%20%2A%3A%22%241%22%3A%2A%29%0A%20%20%20%20%20%20%20%20%20%20%20%20%3B%3B%0A%20%20%20%20%20%20%20%20%2A%29%0A%20%20%20%20%20%20%20%20%20%20%20%20if%20%5B%20%22%242%22%20%3D%20%22after%22%20%5D%20%3B%20then%0A%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20PATH%3D%24PATH%3A%241%0A%20%20%20%20%20%20%20%20%20%20%20%20else%0A%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20PATH%3D%241%3A%24PATH%0A%20%20%20%20%20%20%20%20%20%20%20%20fi%0A%20%20%20%20esac%0A%7D%0A%0A%0Aif%20%5B%20-x%20/usr/bin/id%20%5D%3B%20then%0A%20%20%20%20if%20%5B%20-z%20%22%24EUID%22%20%5D%3B%20then%0A%20%20%20%20%20%20%20%20%23%20ksh%20workaround%0A%20%20%20%20%20%20%20%20EUID%3D%60id%20-u%60%0A%20%20%20%20%20%20%20%20UID%3D%60id%20-ru%60%0A%20%20%20%20fi%0A%20%20%20%20USER%3D%22%60id%20-un%60%22%0A%20%20%20%20LOGNAME%3D%24USER%0A%20%20%20%20MAIL%3D%22/var/spool/mail/%24USER%22%0Afi%0A%0A%23%20Path%20manipulation%0Aif%20%5B%20%22%24EUID%22%20%3D%20%220%22%20%5D%3B%20then%0A%20%20%20%20pathmunge%20/usr/sbin%0A%20%20%20%20pathmunge%20/usr/local/sbin%0Aelse%0A%20%20%20%20pathmunge%20/usr/local/sbin%20after%0A%20%20%20%20pathmunge%20/usr/sbin%20after%0Afi%0A%0AHOSTNAME%3D%60/usr/bin/hostname%202%3E/dev/null%60%0AHISTSIZE%3D1000%0Aif%20%5B%20%22%24HISTCONTROL%22%20%3D%20%22ignorespace%22%20%5D%20%3B%20then%0A%20%20%20%20export%20HISTCONTROL%3Dignoreboth%0Aelse%0A%20%20%20%20export%20HISTCONTROL%3Dignoredups%0Afi%0A%0Aexport%20PATH%20USER%20LOGNAME%20MAIL%20HOSTNAME%20HISTSIZE%20HISTCONTROL%0A%0A%23%20By%20default%2C%20we%20want%20umask%20to%20get%20set.%20This%20sets%20it%20for%20login%20shell%0A%23%20Current%20threshold%20for%20system%20reserved%20uid/gids%20is%20200%0A%23%20You%20could%20check%20uidgid%20reservation%20validity%20in%0A%23%20/usr/share/doc/setup-%2A/uidgid%20file%0Aif%20%5B%20%24UID%20-gt%20199%20%5D%20%26%26%20%5B%20%22%60id%20-gn%60%22%20%3D%20%22%60id%20-un%60%22%20%5D%3B%20then%0A%20%20%20%20umask%20027%0Aelse%0A%20%20%20%20umask%20027%0Afi%0A%0Afor%20i%20in%20/etc/profile.d/%2A.sh%20/etc/profile.d/sh.local%20%3B%20do%0A%20%20%20%20if%20%5B%20-r%20%22%24i%22%20%5D%3B%20then%0A%20%20%20%20%20%20%20%20if%20%5B%20%22%24%7B-%23%2Ai%7D%22%20%21%3D%20%22%24-%22%20%5D%3B%20then%20%0A%20%20%20%20%20%20%20%20%20%20%20%20.%20%22%24i%22%0A%20%20%20%20%20%20%20%20else%0A%20%20%20%20%20%20%20%20%20%20%20%20.%20%22%24i%22%20%3E/dev/null%0A%20%20%20%20%20%20%20%20fi%0A%20%20%20%20fi%0Adone%0A%0Aunset%20i%0Aunset%20-f%20pathmunge%0A%0Aif%20%5B%20-n%20%22%24%7BBASH_VERSION-%7D%22%20%5D%20%3B%20then%0A%20%20%20%20%20%20%20%20if%20%5B%20-f%20/etc/bashrc%20%5D%20%3B%20then%0A%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%23%20Bash%20login%20shells%20run%20only%20/etc/profile%0A%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%23%20Bash%20non-login%20shells%20run%20only%20/etc/bashrc%0A%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%23%20Check%20for%20double%20sourcing%20is%20done%20in%20/etc/bashrc.%0A%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20.%20/etc/bashrc%0A%20%20%20%20%20%20%20fi%0Afi%0A%0A%0A
        mode: 0644
        path: /etc/profile
        overwrite: true

Configure Polyinstantiation of /tmp Directories   [ref]rule

To configure polyinstantiated /tmp directories, first create the parent directories which will hold the polyinstantiation child directories. Use the following command:

$ sudo mkdir --mode 000 /tmp/tmp-inst
Then, add the following entry to /etc/security/namespace.conf:
/tmp     /tmp/tmp-inst/            level      root,adm

Rationale:

Polyinstantiation of temporary directories is a proactive security measure which reduces chances of attacks that are made possible by /tmp directories being world-writable.

Severity:  low

References:  BP28(R39)

Configure Polyinstantiation of /var/tmp Directories   [ref]rule

To configure polyinstantiated /tmp directories, first create the parent directories which will hold the polyinstantiation child directories. Use the following command:

$ sudo mkdir --mode 000 /var/tmp/tmp-inst
Then, add the following entry to /etc/security/namespace.conf:
/var/tmp /var/tmp/tmp-inst/    level      root,adm

Rationale:

Polyinstantiation of temporary directories is a proactive security measure which reduces chances of attacks that are made possible by /var/tmp directories being world-writable.

Severity:  low

References:  BP28(R39)

Set Interactive Session Timeout   [ref]rule

Setting the TMOUT option in /etc/profile ensures that all user sessions will terminate based on inactivity. The value of TMOUT should be exported and read only. The TMOUT setting in a file loaded by /etc/profile, e.g. /etc/profile.d/tmout.sh should read as follows:

declare -xr TMOUT=600

Rationale:

Terminating an idle session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended.

Severity:  medium

System Accounting with auditd   [ref]group

The audit service provides substantial capabilities for recording system activities. By default, the service audits about SELinux AVC denials and certain types of security-relevant events such as system logins, account modifications, and authentication events performed by programs such as sudo. Under its default configuration, auditd has modest disk space requirements, and should not noticeably impact system performance.

NOTE: The Linux Audit daemon auditd can be configured to use the augenrules program to read audit rules files (*.rules) located in /etc/audit/rules.d location and compile them to create the resulting form of the /etc/audit/audit.rules configuration file during the daemon startup (default configuration). Alternatively, the auditd daemon can use the auditctl utility to read audit rules from the /etc/audit/audit.rules configuration file during daemon startup, and load them into the kernel. The expected behavior is configured via the appropriate ExecStartPost directive setting in the /usr/lib/systemd/system/auditd.service configuration file. To instruct the auditd daemon to use the augenrules program to read audit rules (default configuration), use the following setting:

ExecStartPost=-/sbin/augenrules --load
in the /usr/lib/systemd/system/auditd.service configuration file. In order to instruct the auditd daemon to use the auditctl utility to read audit rules, use the following setting:
ExecStartPost=-/sbin/auditctl -R /etc/audit/audit.rules
in the /usr/lib/systemd/system/auditd.service configuration file. Refer to [Service] section of the /usr/lib/systemd/system/auditd.service configuration file for further details.

Government networks often have substantial auditing requirements and auditd can be configured to meet these requirements. Examining some example audit records demonstrates how the Linux audit system satisfies common requirements. The following example from Red Hat Enterprise Linux 7 Documentation available at https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html-single/selinux_users_and_administrators_guide/index#sect-Security-Enhanced_Linux-Fixing_Problems-Raw_Audit_Messages shows the substantial amount of information captured in a two typical "raw" audit messages, followed by a breakdown of the most important fields. In this example the message is SELinux-related and reports an AVC denial (and the associated system call) that occurred when the Apache HTTP Server attempted to access the /var/www/html/file1 file (labeled with the samba_share_t type):
type=AVC msg=audit(1226874073.147:96): avc:  denied  { getattr } for pid=2465 comm="httpd"
path="/var/www/html/file1" dev=dm-0 ino=284133 scontext=unconfined_u:system_r:httpd_t:s0
tcontext=unconfined_u:object_r:samba_share_t:s0 tclass=file

type=SYSCALL msg=audit(1226874073.147:96): arch=40000003 syscall=196 success=no exit=-13
a0=b98df198 a1=bfec85dc a2=54dff4 a3=2008171 items=0 ppid=2463 pid=2465 auid=502 uid=48
gid=48 euid=48 suid=48 fsuid=48 egid=48 sgid=48 fsgid=48 tty=(none) ses=6 comm="httpd"
exe="/usr/sbin/httpd" subj=unconfined_u:system_r:httpd_t:s0 key=(null)
  • msg=audit(1226874073.147:96)
    • The number in parentheses is the unformatted time stamp (Epoch time) for the event, which can be converted to standard time by using the date command.
  • { getattr }
    • The item in braces indicates the permission that was denied. getattr indicates the source process was trying to read the target file's status information. This occurs before reading files. This action is denied due to the file being accessed having the wrong label. Commonly seen permissions include getattr, read, and write.
  • comm="httpd"
    • The executable that launched the process. The full path of the executable is found in the exe= section of the system call (SYSCALL) message, which in this case, is exe="/usr/sbin/httpd".
  • path="/var/www/html/file1"
    • The path to the object (target) the process attempted to access.
  • scontext="unconfined_u:system_r:httpd_t:s0"
    • The SELinux context of the process that attempted the denied action. In this case, it is the SELinux context of the Apache HTTP Server, which is running in the httpd_t domain.
  • tcontext="unconfined_u:object_r:samba_share_t:s0"
    • The SELinux context of the object (target) the process attempted to access. In this case, it is the SELinux context of file1. Note: the samba_share_t type is not accessible to processes running in the httpd_t domain.
  • From the system call (SYSCALL) message, two items are of interest:
    • success=no: indicates whether the denial (AVC) was enforced or not. success=no indicates the system call was not successful (SELinux denied access). success=yes indicates the system call was successful - this can be seen for permissive domains or unconfined domains, such as initrc_t and kernel_t.
    • exe="/usr/sbin/httpd": the full path to the executable that launched the process, which in this case, is exe="/usr/sbin/httpd".

contains 48 rules

Configure auditd Rules for Comprehensive Auditing   [ref]group

The auditd program can perform comprehensive monitoring of system activity. This section describes recommended configuration settings for comprehensive auditing, but a full description of the auditing system's capabilities is beyond the scope of this guide. The mailing list linux-audit@redhat.com exists to facilitate community discussion of the auditing system.

The audit subsystem supports extensive collection of events, including:

  • Tracing of arbitrary system calls (identified by name or number) on entry or exit.
  • Filtering by PID, UID, call success, system call argument (with some limitations), etc.
  • Monitoring of specific files for modifications to the file's contents or metadata.

Auditing rules at startup are controlled by the file /etc/audit/audit.rules. Add rules to it to meet the auditing requirements for your organization. Each line in /etc/audit/audit.rules represents a series of arguments that can be passed to auditctl and can be individually tested during runtime. See documentation in /usr/share/doc/audit-VERSION and in the related man pages for more details.

If copying any example audit rulesets from /usr/share/doc/audit-VERSION, be sure to comment out the lines containing arch= which are not appropriate for your system's architecture. Then review and understand the following rules, ensuring rules are activated as needed for the appropriate architecture.

After reviewing all the rules, reading the following sections, and editing as needed, the new rules can be activated as follows:
$ sudo service auditd restart

contains 46 rules

Record Events that Modify the System's Discretionary Access Controls   [ref]group

At a minimum, the audit system should collect file permission changes for all users and root. Note that the "-F arch=b32" lines should be present even on a 64 bit system. These commands identify system calls for auditing. Even if the system is 64 bit it can still execute 32 bit system calls. Additionally, these rules can be configured in a number of ways while still achieving the desired effect. An example of this is that the "-S" calls could be split up and placed on separate lines, however, this is less efficient. Add the following to /etc/audit/audit.rules:

-a always,exit -F arch=b32 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
    -a always,exit -F arch=b32 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
    -a always,exit -F arch=b32 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If your system is 64 bit then these lines should be duplicated and the arch=b32 replaced with arch=b64 as follows:
-a always,exit -F arch=b64 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
    -a always,exit -F arch=b64 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
    -a always,exit -F arch=b64 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

contains 14 rules

Record Events that Modify the System's Discretionary Access Controls - chmod   [ref]rule

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity:  medium

Identifiers:  CCE-82556-2

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20chmod%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20chmod%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        mode: 0644
        path: /etc/audit/rules.d/75-chmod_dac_modification.rules
        overwrite: true

Record Events that Modify the System's Discretionary Access Controls - chown   [ref]rule

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity:  medium

Identifiers:  CCE-82557-0

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20chown%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20chown%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        mode: 0644
        path: /etc/audit/rules.d/75-chown_dac_modification.rules
        overwrite: true

Record Events that Modify the System's Discretionary Access Controls - fchmod   [ref]rule

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity:  medium

Identifiers:  CCE-82558-8

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20fchmod%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20fchmod%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        mode: 0644
        path: /etc/audit/rules.d/75-fchmod_dac_modification.rules
        overwrite: true

Record Events that Modify the System's Discretionary Access Controls - fchmodat   [ref]rule

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity:  medium

Identifiers:  CCE-82559-6

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20fchmodat%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20fchmodat%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        mode: 0644
        path: /etc/audit/rules.d/75-fchmodat_dac_modification.rules
        overwrite: true

Record Events that Modify the System's Discretionary Access Controls - fchown   [ref]rule

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity:  medium

Identifiers:  CCE-82560-4

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20fchown%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20fchown%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        mode: 0644
        path: /etc/audit/rules.d/75-fchown_dac_modification.rules
        overwrite: true

Record Events that Modify the System's Discretionary Access Controls - fchownat   [ref]rule

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity:  medium

Identifiers:  CCE-82561-2

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20fchownat%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20fchownat%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        mode: 0644
        path: /etc/audit/rules.d/75-fchownat_dac_modification.rules
        overwrite: true

Record Events that Modify the System's Discretionary Access Controls - fremovexattr   [ref]rule

At a minimum, the audit system should collect file permission changes for all users and root.

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity:  medium

Identifiers:  CCE-82562-0

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210, SRG-OS-000468-GPOS-00212, SRG-OS-000064-GPOS-00033, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000499-CTR-001255

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20fremovexattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20fremovexattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        mode: 0644
        path: /etc/audit/rules.d/75-fremovexattr_dac_modification.rules
        overwrite: true

Record Events that Modify the System's Discretionary Access Controls - fsetxattr   [ref]rule

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity:  medium

Identifiers:  CCE-82563-8

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000466-GPOS-00210, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000064-GPOS-00033, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20fsetxattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20fsetxattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        mode: 0644
        path: /etc/audit/rules.d/75-fsetxattr_dac_modification.rules
        overwrite: true

Record Events that Modify the System's Discretionary Access Controls - lchown   [ref]rule

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity:  medium

Identifiers:  CCE-82564-6

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20lchown%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20lchown%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        mode: 0644
        path: /etc/audit/rules.d/75-lchown_dac_modification.rules
        overwrite: true

Record Events that Modify the System's Discretionary Access Controls - lremovexattr   [ref]rule

At a minimum, the audit system should collect file permission changes for all users and root.

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity:  medium

Identifiers:  CCE-82565-3

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210, SRG-OS-000064-GPOS-00033, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20lremovexattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20lremovexattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        mode: 0644
        path: /etc/audit/rules.d/75-lremovexattr_dac_modification.rules
        overwrite: true

Record Events that Modify the System's Discretionary Access Controls - lsetxattr   [ref]rule

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity:  medium

Identifiers:  CCE-82566-1

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000466-GPOS-00210, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000064-GPOS-00033, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20lsetxattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20lsetxattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        mode: 0644
        path: /etc/audit/rules.d/75-lsetxattr_dac_modification.rules
        overwrite: true

Record Events that Modify the System's Discretionary Access Controls - removexattr   [ref]rule

At a minimum, the audit system should collect file permission changes for all users and root.

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod


If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity:  medium

Identifiers:  CCE-82567-9

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210, SRG-OS-000064-GPOS-00033, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20removexattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20removexattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        mode: 0644
        path: /etc/audit/rules.d/75-removexattr_dac_modification.rules
        overwrite: true

Record Events that Modify the System's Discretionary Access Controls - setxattr   [ref]rule

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity:  medium

Identifiers:  CCE-82568-7

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000466-GPOS-00210, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20setxattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20setxattr%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        mode: 0644
        path: /etc/audit/rules.d/75-setxattr_dac_modification.rules
        overwrite: true

Record Events that Modify the System's Discretionary Access Controls - umount2   [ref]rule

At a minimum, the audit system should collect file system umount2 changes. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S umount2 -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S umount2 -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S umount2 -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S umount2 -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity:  medium

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20umount2%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20umount2%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        mode: 0644
        path: /etc/audit/rules.d/75-umount2_dac_modification.rules
        overwrite: true

Record File Deletion Events by User   [ref]group

At a minimum, the audit system should collect file deletion events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S rmdir,unlink,unlinkat,rename,renameat -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S rmdir,unlink,unlinkat,rename,renameat -F auid>=1000 -F auid!=unset -F key=delete

contains 5 rules

Ensure auditd Collects File Deletion Events by User - rename   [ref]rule

At a minimum, the audit system should collect file deletion events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S rename -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S rename -F auid>=1000 -F auid!=unset -F key=delete

Rationale:

Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.

Severity:  medium

Identifiers:  CCE-82575-2

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, 10.2.1.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20rename%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Ddelete%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20rename%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Ddelete%0A
        mode: 0644
        path: /etc/audit/rules.d/75-rename-file-deletion-events.rules
        overwrite: true

Ensure auditd Collects File Deletion Events by User - renameat   [ref]rule

At a minimum, the audit system should collect file deletion events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S renameat -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S renameat -F auid>=1000 -F auid!=unset -F key=delete

Rationale:

Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.

Severity:  medium

Identifiers:  CCE-82576-0

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, 10.2.1.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20renameat%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Ddelete%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20renameat%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Ddelete%0A
        mode: 0644
        path: /etc/audit/rules.d/75-renameat-file-deletion-events.rules
        overwrite: true

Ensure auditd Collects File Deletion Events by User - rmdir   [ref]rule

At a minimum, the audit system should collect file deletion events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S rmdir -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S rmdir -F auid>=1000 -F auid!=unset -F key=delete

Rationale:

Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.

Severity:  medium

Identifiers:  CCE-82577-8

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, 10.2.1.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20rmdir%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Ddelete%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20rmdir%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Ddelete%0A
        mode: 0644
        path: /etc/audit/rules.d/75-rmdir-file-deletion-events.rules
        overwrite: true

Ensure auditd Collects File Deletion Events by User - unlinkat   [ref]rule

At a minimum, the audit system should collect file deletion events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete

Rationale:

Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.

Severity:  medium

Identifiers:  CCE-82579-4

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, 10.2.1.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20unlinkat%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Ddelete%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20unlinkat%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Ddelete%0A
        mode: 0644
        path: /etc/audit/rules.d/75-unlinkat-file-deletion-events.rules
        overwrite: true

Record Unauthorized Access Attempts Events to Files (unsuccessful)   [ref]group

At a minimum, the audit system should collect unauthorized file accesses for all users and root. Note that the "-F arch=b32" lines should be present even on a 64 bit system. These commands identify system calls for auditing. Even if the system is 64 bit it can still execute 32 bit system calls. Additionally, these rules can be configured in a number of ways while still achieving the desired effect. An example of this is that the "-S" calls could be split up and placed on separate lines, however, this is less efficient. Add the following to /etc/audit/audit.rules:

-a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If your system is 64 bit then these lines should be duplicated and the arch=b32 replaced with arch=b64 as follows:
-a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

contains 5 rules

Record Unsuccessful Access Attempts to Files - creat   [ref]rule

At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

Severity:  medium

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable
---

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,{{ %23%23%20This%20content%20is%20a%20section%20of%20an%20Audit%20config%20snapshot%20recommended%20for%20Red%2520Hat%2520Enterprise%2520Linux%2520CoreOS%25204%20systems%20that%20target%20OSPP%20compliance.%0A%23%23%20The%20following%20content%20has%20been%20retreived%20on%202019-03-11%20from%3A%20https%3A//github.com/linux-audit/audit-userspace/blob/master/rules/30-ospp-v42.rules%0A%0A%23%23%20The%20purpose%20of%20these%20rules%20is%20to%20meet%20the%20requirements%20for%20Operating%0A%23%23%20System%20Protection%20Profile%20%28OSPP%29v4.2.%20These%20rules%20depends%20on%20having%0A%23%23%2010-base-config.rules%2C%2011-loginuid.rules%2C%20and%2043-module-load.rules%20installed.%0A%0A%23%23%20Unsuccessful%20file%20creation%20%28open%20with%20O_CREAT%29%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20creat%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20creat%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20creat%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20creat%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A%0A%23%23%20Unsuccessful%20file%20modifications%20%28open%20for%20write%20or%20truncate%29%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A%0A%23%23%20Unsuccessful%20file%20access%20%28any%20other%20opens%29%20This%20has%20to%20go%20last.%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%2Ccreat%2Ctruncate%2Cftruncate%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-access%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%2Ccreat%2Ctruncate%2Cftruncate%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-access%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%2Ccreat%2Ctruncate%2Cftruncate%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-access%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%2Ccreat%2Ctruncate%2Cftruncate%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-access }}
        mode: 0600
        path: /etc/audit/rules.d/30-ospp-v42-remediation.rules
        overwrite: true

Record Unsuccessful Access Attempts to Files - ftruncate   [ref]rule

At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

Severity:  medium

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable
---

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,{{ %23%23%20This%20content%20is%20a%20section%20of%20an%20Audit%20config%20snapshot%20recommended%20for%20Red%2520Hat%2520Enterprise%2520Linux%2520CoreOS%25204%20systems%20that%20target%20OSPP%20compliance.%0A%23%23%20The%20following%20content%20has%20been%20retreived%20on%202019-03-11%20from%3A%20https%3A//github.com/linux-audit/audit-userspace/blob/master/rules/30-ospp-v42.rules%0A%0A%23%23%20The%20purpose%20of%20these%20rules%20is%20to%20meet%20the%20requirements%20for%20Operating%0A%23%23%20System%20Protection%20Profile%20%28OSPP%29v4.2.%20These%20rules%20depends%20on%20having%0A%23%23%2010-base-config.rules%2C%2011-loginuid.rules%2C%20and%2043-module-load.rules%20installed.%0A%0A%23%23%20Unsuccessful%20file%20creation%20%28open%20with%20O_CREAT%29%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20creat%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20creat%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20creat%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20creat%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A%0A%23%23%20Unsuccessful%20file%20modifications%20%28open%20for%20write%20or%20truncate%29%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A%0A%23%23%20Unsuccessful%20file%20access%20%28any%20other%20opens%29%20This%20has%20to%20go%20last.%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%2Ccreat%2Ctruncate%2Cftruncate%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-access%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%2Ccreat%2Ctruncate%2Cftruncate%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-access%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%2Ccreat%2Ctruncate%2Cftruncate%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-access%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%2Ccreat%2Ctruncate%2Cftruncate%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-access }}
        mode: 0600
        path: /etc/audit/rules.d/30-ospp-v42-remediation.rules
        overwrite: true

Record Unsuccessful Access Attempts to Files - open   [ref]rule

At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

Severity:  medium

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable
---

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,{{ %23%23%20This%20content%20is%20a%20section%20of%20an%20Audit%20config%20snapshot%20recommended%20for%20Red%2520Hat%2520Enterprise%2520Linux%2520CoreOS%25204%20systems%20that%20target%20OSPP%20compliance.%0A%23%23%20The%20following%20content%20has%20been%20retreived%20on%202019-03-11%20from%3A%20https%3A//github.com/linux-audit/audit-userspace/blob/master/rules/30-ospp-v42.rules%0A%0A%23%23%20The%20purpose%20of%20these%20rules%20is%20to%20meet%20the%20requirements%20for%20Operating%0A%23%23%20System%20Protection%20Profile%20%28OSPP%29v4.2.%20These%20rules%20depends%20on%20having%0A%23%23%2010-base-config.rules%2C%2011-loginuid.rules%2C%20and%2043-module-load.rules%20installed.%0A%0A%23%23%20Unsuccessful%20file%20creation%20%28open%20with%20O_CREAT%29%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20creat%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20creat%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20creat%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20creat%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A%0A%23%23%20Unsuccessful%20file%20modifications%20%28open%20for%20write%20or%20truncate%29%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A%0A%23%23%20Unsuccessful%20file%20access%20%28any%20other%20opens%29%20This%20has%20to%20go%20last.%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%2Ccreat%2Ctruncate%2Cftruncate%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-access%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%2Ccreat%2Ctruncate%2Cftruncate%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-access%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%2Ccreat%2Ctruncate%2Cftruncate%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-access%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%2Ccreat%2Ctruncate%2Cftruncate%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-access }}
        mode: 0600
        path: /etc/audit/rules.d/30-ospp-v42-remediation.rules
        overwrite: true

Record Unsuccessful Access Attempts to Files - openat   [ref]rule

At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

Severity:  medium

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable
---

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,{{ %23%23%20This%20content%20is%20a%20section%20of%20an%20Audit%20config%20snapshot%20recommended%20for%20Red%2520Hat%2520Enterprise%2520Linux%2520CoreOS%25204%20systems%20that%20target%20OSPP%20compliance.%0A%23%23%20The%20following%20content%20has%20been%20retreived%20on%202019-03-11%20from%3A%20https%3A//github.com/linux-audit/audit-userspace/blob/master/rules/30-ospp-v42.rules%0A%0A%23%23%20The%20purpose%20of%20these%20rules%20is%20to%20meet%20the%20requirements%20for%20Operating%0A%23%23%20System%20Protection%20Profile%20%28OSPP%29v4.2.%20These%20rules%20depends%20on%20having%0A%23%23%2010-base-config.rules%2C%2011-loginuid.rules%2C%20and%2043-module-load.rules%20installed.%0A%0A%23%23%20Unsuccessful%20file%20creation%20%28open%20with%20O_CREAT%29%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20creat%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20creat%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20creat%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20creat%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A%0A%23%23%20Unsuccessful%20file%20modifications%20%28open%20for%20write%20or%20truncate%29%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%2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}}
        mode: 0600
        path: /etc/audit/rules.d/30-ospp-v42-remediation.rules
        overwrite: true

Record Unsuccessful Access Attempts to Files - truncate   [ref]rule

At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Warning:  Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.
Rationale:

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

Severity:  medium

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable
---

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,{{ %23%23%20This%20content%20is%20a%20section%20of%20an%20Audit%20config%20snapshot%20recommended%20for%20Red%2520Hat%2520Enterprise%2520Linux%2520CoreOS%25204%20systems%20that%20target%20OSPP%20compliance.%0A%23%23%20The%20following%20content%20has%20been%20retreived%20on%202019-03-11%20from%3A%20https%3A//github.com/linux-audit/audit-userspace/blob/master/rules/30-ospp-v42.rules%0A%0A%23%23%20The%20purpose%20of%20these%20rules%20is%20to%20meet%20the%20requirements%20for%20Operating%0A%23%23%20System%20Protection%20Profile%20%28OSPP%29v4.2.%20These%20rules%20depends%20on%20having%0A%23%23%2010-base-config.rules%2C%2011-loginuid.rules%2C%20and%2043-module-load.rules%20installed.%0A%0A%23%23%20Unsuccessful%20file%20creation%20%28open%20with%20O_CREAT%29%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%260100%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20creat%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20creat%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20creat%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20creat%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-create%0A%0A%23%23%20Unsuccessful%20file%20modifications%20%28open%20for%20write%20or%20truncate%29%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20openat%2Copen_by_handle_at%20-F%20a2%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%20-F%20a1%2601003%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20truncate%2Cftruncate%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-modification%0A%0A%23%23%20Unsuccessful%20file%20access%20%28any%20other%20opens%29%20This%20has%20to%20go%20last.%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%2Ccreat%2Ctruncate%2Cftruncate%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-access%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%2Ccreat%2Ctruncate%2Cftruncate%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EACCES%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-access%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20open%2Ccreat%2Ctruncate%2Cftruncate%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-access%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20open%2Ccreat%2Ctruncate%2Cftruncate%2Copenat%2Copen_by_handle_at%20-F%20exit%3D-EPERM%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dunsuccesful-access }}
        mode: 0600
        path: /etc/audit/rules.d/30-ospp-v42-remediation.rules
        overwrite: true

Record Information on Kernel Modules Loading and Unloading   [ref]group

To capture kernel module loading and unloading events, use following lines, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:

-a always,exit -F arch=ARCH -S init_module,delete_module -F key=modules
Place to add the lines depends on a way auditd daemon is configured. If it is configured to use the augenrules program (the default), add the lines to a file with suffix .rules in the directory /etc/audit/rules.d. If the auditd daemon is configured to use the auditctl utility, add the lines to file /etc/audit/audit.rules.

contains 3 rules

Ensure auditd Collects Information on Kernel Module Unloading - delete_module   [ref]rule

To capture kernel module unloading events, use following line, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:

-a always,exit -F arch=ARCH -S delete_module -F key=modules
Place to add the line depends on a way auditd daemon is configured. If it is configured to use the augenrules program (the default), add the line to a file with suffix .rules in the directory /etc/audit/rules.d. If the auditd daemon is configured to use the auditctl utility, add the line to file /etc/audit/audit.rules.

Rationale:

The removal of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20delete_module%20-k%20module-change%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20delete_module%20-k%20module-change%0A
        mode: 0600
        path: /etc/audit/rules.d/75-kernel-module-loading-delete.rules
        overwrite: true

Ensure auditd Collects Information on Kernel Module Loading and Unloading - finit_module   [ref]rule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d to capture kernel module loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S finit_module -F key=modules
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file in order to capture kernel module loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S finit_module -F key=modules

Rationale:

The addition/removal of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20finit_module%20-k%20module-change%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20finit_module%20-k%20module-change%0A
        mode: 0600
        path: /etc/audit/rules.d/75-kernel-module-loading-finit.rules
        overwrite: true

Ensure auditd Collects Information on Kernel Module Loading - init_module   [ref]rule

To capture kernel module loading events, use following line, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:

-a always,exit -F arch=ARCH -S init_module -F key=modules
Place to add the line depends on a way auditd daemon is configured. If it is configured to use the augenrules program (the default), add the line to a file with suffix .rules in the directory /etc/audit/rules.d. If the auditd daemon is configured to use the auditctl utility, add the line to file /etc/audit/audit.rules.

Rationale:

The addition of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20init_module%20-k%20module-change%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20init_module%20-k%20module-change%0A
        mode: 0600
        path: /etc/audit/rules.d/75-kernel-module-loading-init.rules
        overwrite: true
contains 2 rules

Record Information on the Use of Privileged Commands   [ref]group

At a minimum, the audit system should collect the execution of privileged commands for all users and root.

contains 2 rules

Ensure auditd Collects Information on the Use of Privileged Commands   [ref]rule

The audit system should collect information about usage of privileged commands for all users. These are commands with suid or sgid bits on and they are specially risky in local block device partitions not mounted with noexec and nosuid options. Therefore, these partitions should be first identified by the following command:

findmnt -n -l -k -it $(awk '/nodev/ { print $2 }' /proc/filesystems | paste -sd,) | grep -Pv "noexec|nosuid"
For all partitions listed by the previous command, it is necessary to search for setuid / setgid programs using the following command:
$ sudo find PARTITION -xdev -perm /6000 -type f 2>/dev/null
For each setuid / setgid program identified by the previous command, an audit rule must be present in the appropriate place using the following line structure:
-a always,exit -F path=PROG_PATH -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the line to a file with suffix .rules in the /etc/audit/rules.d directory, replacing the PROG_PATH part with the full path of that setuid / setgid identified program. If the auditd daemon is configured to use the auditctl utility instead, add the line to the /etc/audit/audit.rules file, also replacing the PROG_PATH part with the full path of that setuid / setgid identified program.

Warning:  This rule checks for multiple syscalls related to privileged commands. If needed to check specific privileged commands, other more specific rules should be considered. For example:
  • audit_rules_privileged_commands_su
  • audit_rules_privileged_commands_umount
  • audit_rules_privileged_commands_passwd
Warning:  Note that OVAL check and Bash / Ansible remediation of this rule explicitly excludes file systems mounted at
/proc
directory and its subdirectories. It is a virtual file system and it doesn't contain executable applications. At the same time, interacting with this file system during check or remediation caused undesirable errors.
Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern that can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity:  medium

Ensure auditd Collects Information on the Use of Privileged Commands - sudo   [ref]rule

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:
-a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity:  medium

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20path%3D/usr/bin/sudo%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dprivileged%0A
        mode: 0644
        path: /etc/audit/rules.d/75-usr_bin_sudo_execution.rules
        overwrite: true

Records Events that Modify Date and Time Information   [ref]group

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time. All changes to the system time should be audited.

contains 4 rules

Record attempts to alter time through adjtimex   [ref]rule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S adjtimex -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S adjtimex -F key=audit_time_rules
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S adjtimex -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S adjtimex -F key=audit_time_rules
The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules

Rationale:

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

Severity:  medium

Remediation script:   (show)

Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,{{ -a%20always%2Cexit%20-F%20arch%3Db64%20-S%20adjtimex%20-k%20audit_time_rules%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20adjtimex%20-k%20audit_time_rules%0A }}
        mode: 0600
        path: /etc/audit/rules.d/75-syscall-adjtimex.rules
        overwrite: true

Record Attempts to Alter Time Through clock_settime   [ref]rule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S clock_settime -F a0=0x0 -F key=time-change
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S clock_settime -F a0=0x0 -F key=time-change
The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules

Rationale:

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

Severity:  medium

Remediation script:   (show)

Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,{{ -a%20always%2Cexit%20-F%20arch%3Db64%20-S%20clock_settime%20-F%20a0%3D0x0%20-k%20time-change%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20clock_settime%20-F%20a0%3D0x0%20-k%20time-change%0A }}
        mode: 0600
        path: /etc/audit/rules.d/75-syscall-clock-settime.rules
        overwrite: true

Record Attempts to Alter Time Through stime   [ref]rule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d for both 32 bit and 64 bit systems:

-a always,exit -F arch=b32 -S stime -F key=audit_time_rules
Since the 64 bit version of the "stime" system call is not defined in the audit lookup table, the corresponding "-F arch=b64" form of this rule is not expected to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule form itself is sufficient for both 32 bit and 64 bit systems). If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file for both 32 bit and 64 bit systems:
-a always,exit -F arch=b32 -S stime -F key=audit_time_rules
Since the 64 bit version of the "stime" system call is not defined in the audit lookup table, the corresponding "-F arch=b64" form of this rule is not expected to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule form itself is sufficient for both 32 bit and 64 bit systems). The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined system calls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules

Rationale:

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

Severity:  medium

Remediation script:   (show)

Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,{{ -a%20always%2Cexit%20-F%20arch%3Db64%20-S%20stime%20-k%20audit_time_rules%0A-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20stime%20-k%20audit_time_rules%0A }}
        mode: 0600
        path: /etc/audit/rules.d/75-syscall-stime.rules
        overwrite: true

Record Attempts to Alter the localtime File   [ref]rule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-w /etc/localtime -p wa -k audit_time_rules
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-w /etc/localtime -p wa -k audit_time_rules
The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport and should always be used.

Rationale:

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

Severity:  medium

Remediation script:   (show)

Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,{{ -w%20/etc/localtime%20-p%20wa%20-k%20audit_time_rules%0A }}
        mode: 0600
        path: /etc/audit/rules.d/75-etclocaltime-wa-audit_time_rules.rules
        overwrite: true

Make the auditd Configuration Immutable   [ref]rule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d in order to make the auditd configuration immutable:

-e 2
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file in order to make the auditd configuration immutable:
-e 2
With this setting, a reboot will be required to change any audit rules.

Rationale:

Making the audit configuration immutable prevents accidental as well as malicious modification of the audit rules, although it may be problematic if legitimate changes are needed during system operation.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-e%202%0A
        mode: 0600
        path: /etc/audit/rules.d/90-immutable.rules
        overwrite: true

Record Events that Modify the System's Mandatory Access Controls   [ref]rule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-w /etc/selinux/ -p wa -k MAC-policy
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-w /etc/selinux/ -p wa -k MAC-policy

Rationale:

The system's mandatory access policy (SELinux) should not be arbitrarily changed by anything other than administrator action. All changes to MAC policy should be audited.

Severity:  medium

Remediation script:   (show)

Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
---

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,{{ -w%20/etc/selinux/%20-p%20wa%20-k%20MAC-policy%0A }}
        mode: 0600
        path: /etc/audit/rules.d/75-etcselinux-wa-MAC-policy.rules
        overwrite: true

Ensure auditd Collects Information on Exporting to Media (successful)   [ref]rule

At a minimum, the audit system should collect media exportation events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export

Rationale:

The unauthorized exportation of data to external media could result in an information leak where classified information, Privacy Act information, and intellectual property could be lost. An audit trail should be created each time a filesystem is mounted to help identify and guard against information loss.

Severity:  medium

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20mount%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20mount%20-F%20auid%3E%3D1000%20-F%20auid%21%3Dunset%20-F%20key%3Dperm_mod%0A
        mode: 0644
        path: /etc/audit/rules.d/75-mount_dac_modification.rules
        overwrite: true

Record Events that Modify the System's Network Environment   [ref]rule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S sethostname,setdomainname -F key=audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification
-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S sethostname,setdomainname -F key=audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification
-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification

Rationale:

The network environment should not be modified by anything other than administrator action. Any change to network parameters should be audited.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-a%20always%2Cexit%20-F%20arch%3Db32%20-S%20sethostname%2Csetdomainname%20-F%20key%3Daudit_rules_networkconfig_modification%0A-a%20always%2Cexit%20-F%20arch%3Db64%20-S%20sethostname%2Csetdomainname%20-F%20key%3Daudit_rules_networkconfig_modification%0A-w%20/etc/issue%20-p%20wa%20-k%20audit_rules_networkconfig_modification%0A-w%20/etc/issue.net%20-p%20wa%20-k%20audit_rules_networkconfig_modification%0A-w%20/etc/hosts%20-p%20wa%20-k%20audit_rules_networkconfig_modification%0A-w%20/etc/sysconfig/network%20-p%20wa%20-k%20audit_rules_networkconfig_modification%0A
        mode: 0644
        path: /etc/audit/rules.d/75-audit_rules_networkconfig_modification.rules
        overwrite: true

Record Attempts to Alter Process and Session Initiation Information   [ref]rule

The audit system already collects process information for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d in order to watch for attempted manual edits of files involved in storing such process information:

-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file in order to watch for attempted manual edits of files involved in storing such process information:
-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session

Rationale:

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

Severity:  medium

Remediation script:   (show)

Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
---


apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,{{ %0A-w%20/var/run/utmp%20-p%20wa%20-k%20session%0A-w%20/var/log/btmp%20-p%20wa%20-k%20session%0A-w%20/var/log/wtmp%20-p%20wa%20-k%20session%0A }}
        mode: 0600
        path: /etc/audit/rules.d/75-audit-session-events.rules
        overwrite: true

Ensure auditd Collects System Administrator Actions   [ref]rule

At a minimum, the audit system should collect administrator actions for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-w /etc/sudoers -p wa -k actions
-w /etc/sudoers.d/ -p wa -k actions
If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:
-w /etc/sudoers -p wa -k actions
-w /etc/sudoers.d/ -p wa -k actions

Rationale:

The actions taken by system administrators should be audited to keep a record of what was executed on the system, as well as, for accountability purposes.

Severity:  medium

Identifiers:  CCE-82613-1

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, AC-2(7)(b), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.2, Req-10.2.5.b, 10.2.1.5, 10.2.2, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-APP-000026-CTR-000070, SRG-APP-000027-CTR-000075, SRG-APP-000028-CTR-000080, SRG-APP-000291-CTR-000675, SRG-APP-000292-CTR-000680, SRG-APP-000293-CTR-000685, SRG-APP-000294-CTR-000690, SRG-APP-000319-CTR-000745, SRG-APP-000320-CTR-000750, SRG-APP-000509-CTR-001305

Remediation script:   (show)

Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,{{ -w%20/etc/sudoers.d/%20-p%20wa%20-k%20actions%0A-w%20/etc/sudoers%20-p%20wa%20-k%20actions%0A }}
        mode: 0600
        path: /etc/audit/rules.d/75-audit-sysadmin-actions.rules
        overwrite: true

Record Events that Modify User/Group Information - /etc/group   [ref]rule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, in order to capture events that modify account changes:

-w /etc/group -p wa -k audit_rules_usergroup_modification


If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file, in order to capture events that modify account changes:

-w /etc/group -p wa -k audit_rules_usergroup_modification

Rationale:

In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.

Severity:  medium

Identifiers:  CCE-82654-5

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, 10.2.1.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000503-CTR-001275

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-w%20/etc/group%20-p%20wa%20-k%20audit_rules_usergroup_modification%0A
        mode: 0644
        path: /etc/audit/rules.d/30-etc_group_usergroup_modification.rules
        overwrite: true

Record Events that Modify User/Group Information - /etc/gshadow   [ref]rule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, in order to capture events that modify account changes:

-w /etc/gshadow -p wa -k audit_rules_usergroup_modification


If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file, in order to capture events that modify account changes:

-w /etc/gshadow -p wa -k audit_rules_usergroup_modification

Rationale:

In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.

Severity:  medium

Identifiers:  CCE-82655-2

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, 10.2.1.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000503-CTR-001275

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-w%20/etc/gshadow%20-p%20wa%20-k%20audit_rules_usergroup_modification%0A
        mode: 0644
        path: /etc/audit/rules.d/30-etc_gshadow_usergroup_modification.rules
        overwrite: true

Record Events that Modify User/Group Information - /etc/security/opasswd   [ref]rule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, in order to capture events that modify account changes:

-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification


If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file, in order to capture events that modify account changes:

-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification

Rationale:

In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.

Severity:  medium

Identifiers:  CCE-82656-0

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, 10.2.1.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000503-CTR-001275

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-w%20/etc/security/opasswd%20-p%20wa%20-k%20audit_rules_usergroup_modification%0A
        mode: 0644
        path: /etc/audit/rules.d/30-etc_security_opasswd_usergroup_modification.rules
        overwrite: true

Record Events that Modify User/Group Information - /etc/passwd   [ref]rule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, in order to capture events that modify account changes:

-w /etc/passwd -p wa -k audit_rules_usergroup_modification


If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file, in order to capture events that modify account changes:

-w /etc/passwd -p wa -k audit_rules_usergroup_modification

Rationale:

In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.

Severity:  medium

Identifiers:  CCE-82657-8

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, 10.2.1.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-OS-000274-GPOS-00104, SRG-OS-000275-GPOS-00105, SRG-OS-000276-GPOS-00106, SRG-OS-000277-GPOS-00107, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000503-CTR-001275

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-w%20/etc/passwd%20-p%20wa%20-k%20audit_rules_usergroup_modification%0A
        mode: 0644
        path: /etc/audit/rules.d/30-etc_passwd_usergroup_modification.rules
        overwrite: true

Record Events that Modify User/Group Information - /etc/shadow   [ref]rule

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, in order to capture events that modify account changes:

-w /etc/shadow -p wa -k audit_rules_usergroup_modification


If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file, in order to capture events that modify account changes:

-w /etc/shadow -p wa -k audit_rules_usergroup_modification

Rationale:

In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.

Severity:  medium

Identifiers:  CCE-82658-6

References:  BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, 10.2.1.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000503-CTR-001275

Remediation script:   (show)

Complexity:low
Disruption:medium
Reboot:true
Strategy:disable

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,-w%20/etc/shadow%20-p%20wa%20-k%20audit_rules_usergroup_modification%0A
        mode: 0644
        path: /etc/audit/rules.d/30-etc_shadow_usergroup_modification.rules
        overwrite: true

Ensure the audit Subsystem is Installed   [ref]rule

The audit package should be installed.

Rationale:

The auditd service is an access monitoring and accounting daemon, watching system calls to audit any access, in comparison with potential local access control policy such as SELinux policy.

Severity:  medium

Enable auditd Service   [ref]rule

The auditd service is an essential userspace component of the Linux Auditing System, as it is responsible for writing audit records to disk. The auditd service can be enabled with the following manifest:

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
  labels:
    machineconfiguration.openshift.io/role: master
  name: 75-master-auditd-enable
spec:
  config:
    ignition:
      version: 3.1.0
    systemd:
      units:
      - name: auditd.service
        enabled: true

This will enable the auditd service in all the nodes labeled with the "master" role.

Note that this needs to be done for each MachineConfigPool

For more information on how to configure nodes with the Machine Config Operator see the relevant documentation.

Rationale:

Without establishing what type of events occurred, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack. Ensuring the auditd service is active ensures audit records generated by the kernel are appropriately recorded.

Additionally, a properly configured audit subsystem ensures that actions of individual system users can be uniquely traced to those users so they can be held accountable for their actions.

Severity:  medium

Identifiers:  CCE-82463-1

References:  BP28(R33), BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.3.1, 3.3.2, 3.3.6, CCI-000126, CCI-000130, CCI-000131, CCI-000132, CCI-000133, CCI-000134, CCI-000135, CCI-000154, CCI-000158, CCI-000172, CCI-000366, CCI-001464, CCI-001487, CCI-001814, CCI-001875, CCI-001876, CCI-001877, CCI-002884, CCI-001878, CCI-001879, CCI-001880, CCI-001881, CCI-001882, CCI-001889, CCI-001914, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(C), 164.310(a)(2)(iv), 164.310(d)(2)(iii), 164.312(b), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, CIP-004-6 R3.3, CIP-007-3 R6.5, AC-2(g), AU-3, AU-10, AU-2(d), AU-12(c), AU-14(1), AC-6(9), CM-6(a), SI-4(23), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1, Req-10.1, 10.2.1, SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000038-GPOS-00016, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000041-GPOS-00019, SRG-OS-000042-GPOS-00021, SRG-OS-000051-GPOS-00024, SRG-OS-000054-GPOS-00025, SRG-OS-000122-GPOS-00063, SRG-OS-000254-GPOS-00095, SRG-OS-000255-GPOS-00096, SRG-OS-000337-GPOS-00129, SRG-OS-000348-GPOS-00136, SRG-OS-000349-GPOS-00137, SRG-OS-000350-GPOS-00138, SRG-OS-000351-GPOS-00139, SRG-OS-000352-GPOS-00140, SRG-OS-000353-GPOS-00141, SRG-OS-000354-GPOS-00142, SRG-OS-000358-GPOS-00145, SRG-OS-000365-GPOS-00152, SRG-OS-000392-GPOS-00172, SRG-OS-000475-GPOS-00220, SRG-APP-000095-CTR-000170, SRG-APP-000409-CTR-000990, SRG-APP-000508-CTR-001300, SRG-APP-000510-CTR-001310

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    systemd:
      units:
      - name: auditd.service
        enabled: true

GRUB2 bootloader configuration   [ref]group

During the boot process, the boot loader is responsible for starting the execution of the kernel and passing options to it. The boot loader allows for the selection of different kernels - possibly on different partitions or media. The default Red Hat Enterprise Linux CoreOS 4 boot loader for x86 systems is called GRUB2. Options it can pass to the kernel include single-user mode, which provides root access without any authentication, and the ability to disable SELinux. To prevent local users from modifying the boot parameters and endangering security, protect the boot loader configuration with a password and ensure its configuration file's permissions are set properly.

contains 10 rules

UEFI GRUB2 bootloader configuration   [ref]group

UEFI GRUB2 bootloader configuration

Warning:  UEFI generally uses vfat file systems, which does not support Unix-style permissions managed by chmod command. In this case, in order to change file permissions for files within /boot/efi it is necessary to update the mount options in /etc/fstab file and reboot the system.
contains 1 rule

Set the UEFI Boot Loader Password   [ref]rule

The grub2 boot loader should have a superuser account and password protection enabled to protect boot-time settings.

Since plaintext passwords are a security risk, generate a hash for the password by running the following command:

# grub2-setpassword
When prompted, enter the password that was selected.

Warning:  To prevent hard-coded passwords, automatic remediation of this control is not available. Remediation must be automated as a component of machine provisioning, or followed manually as outlined above. Also, do NOT manually add the superuser account and password to the grub.cfg file as the grub2-mkconfig command overwrites this file.
Rationale:

Password protection on the boot loader configuration ensures users with physical access cannot trivially alter important bootloader settings. These include which kernel to use, and whether to enter single-user mode.

Severity:  high

IOMMU configuration directive   [ref]rule

On x86 architecture supporting VT-d, the IOMMU manages the access control policy between the hardware devices and some of the system critical units such as the memory. Configure the default Grub2 kernel command line to contain iommu=force as follows:

# grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) iommu=force"

Warning:  Depending on the hardware, devices and operating system used, enabling IOMMU can cause hardware instabilities. Proper function and stability should be assessed before applying remediation to production systems.
Rationale:

On x86 architectures, activating the I/OMMU prevents the system from arbitrary accesses potentially made by hardware devices.

Severity:  unknown

References:  BP28(R11)

Configure L1 Terminal Fault mitigations   [ref]rule

L1 Terminal Fault (L1TF) is a hardware vulnerability which allows unprivileged speculative access to data which is available in the Level 1 Data Cache when the page table entry isn't present. Select the appropriate mitigation by adding the argument l1tf=full,force to the default GRUB 2 command line for the Linux operating system. Configure the default Grub2 kernel command line to contain l1tf=full,force as follows:

# grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) l1tf=full,force"
Since Linux Kernel 4.19 you can check the L1TF vulnerability state with the following command: cat /sys/devices/system/cpu/vulnerabilities/l1tf

Warning:  Enabling L1TF mitigations may impact performance of the system.
Rationale:

The L1TF vulnerability allows an attacker to bypass memory access security controls imposed by the system or hypervisor. The L1TF vulnerability allows read access to any physical memory location that is cached in the L1 Data Cache.

Severity:  high

References:  BP28(R8)

Force kernel panic on uncorrected MCEs   [ref]rule

A Machine Check Exception is an error generated by the CPU itdetects an error in itself, memory or I/O devices. These errors may be corrected and generate a check log entry, if an error cannot be corrected the kernel may panic or SIGBUS. To force the kernel to panic on any uncorrected error reported by Machine Check set the MCE tolerance to zero by adding mce=0 to the default GRUB 2 command line for the Linux operating system. Configure the default Grub2 kernel command line to contain mce=0 as follows:

# grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) mce=0"

Rationale:

Allowing uncorrected errors to result on a SIGBUS may allow an attacker to continue trying to exploit a vulnerability such as Rowhammer.

Severity:  medium

References:  BP28(R8)

Ensure SMAP is not disabled during boot   [ref]rule

The SMAP is used to prevent the supervisor mode from unintentionally reading/writing into memory pages in the user space, it is enabled by default since Linux kernel 3.7. But it could be disabled through kernel boot parameters. Ensure that Supervisor Mode Access Prevention (SMAP) is not disabled by the nosmap boot paramenter option. Check that the line

GRUB_CMDLINE_LINUX="..."
within /etc/default/grub doesn't contain the argument nosmap. Run the following command to update command line for already installed kernels:
# grubby --update-kernel=ALL --remove-args="nosmap"

Rationale:

Disabling SMAP can facilitate exploitation of vulnerabilities caused by unintended access and manipulation of data in the user space.

Severity:  medium

References:  BP28(R1)

Ensure SMEP is not disabled during boot   [ref]rule

The SMEP is used to prevent the supervisor mode from executing user space code, it is enabled by default since Linux kernel 3.0. But it could be disabled through kernel boot parameters. Ensure that Supervisor Mode Execution Prevention (SMEP) is not disabled by the nosmep boot paramenter option. Check that the line

GRUB_CMDLINE_LINUX="..."
within /etc/default/grub doesn't contain the argument nosmep. Run the following command to update command line for already installed kernels:
# grubby --update-kernel=ALL --remove-args="nosmep"

Rationale:

Disabling SMEP can facilitate exploitation of certain vulnerabilities because it allows the kernel to unintentionally execute code in less privileged memory space.

Severity:  medium

References:  BP28(R1)

Configure the confidence in TPM for entropy   [ref]rule

The TPM security chip that is available in most modern systems has a hardware RNG. It is also used to feed the entropy pool, but generally not credited entropy. Use rng_core.default_quality in the kernel command line to set the trust level on the hardware generators. The trust level defines the amount of entropy to credit. A value of 0 tells the system not to trust the hardware random number generators available, and doesn't credit any entropy to the pool. A value of 1000 assigns full confidence in the generators, and credits all the entropy it provides to the pool. Note that the value of rng_core.default_quality is global, affecting the trust on all hardware random number generators. Select the appropriate confidence by adding the argument rng_core.default_quality=500 to the default GRUB 2 command line for the Linux operating system. Configure the default Grub2 kernel command line to contain rng_core.default_quality=500 as follows:

# grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) rng_core.default_quality=500"

Rationale:

A system may struggle to initialize its entropy pool and end up starving. Crediting entropy from the hardware number generators available in the system helps fill up the entropy pool.

Severity:  low

References:  BP28(R8)

Disable merging of slabs with similar size   [ref]rule

The kernel may merge similar slabs together to reduce overhead and increase cache hotness of objects. Disabling merging of slabs keeps the slabs separate and reduces the risk of kernel heap overflows overwriting objects in merged caches. To disable merging of slabs in the Kernel add the argument slab_nomerge=yes to the default GRUB 2 command line for the Linux operating system. Configure the default Grub2 kernel command line to contain slab_nomerge=yes as follows:

# grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) slab_nomerge=yes"

Warning:  Disabling merge of slabs will slightly increase kernel memory utilization.
Rationale:

Disabling the merge of slabs of similar sizes prevents the kernel from merging a seemingly useless but vulnerable slab with a useful and valuable slab. This increase the risk that a heap overflow could overwrite objects from merged caches, with unmerged caches the heap overflow would only affect the objects in the same cache. Overall, this reduces the kernel attack surface area by isolating slabs from each other.

Severity:  medium

References:  BP28(R8)

Configure Speculative Store Bypass Mitigation   [ref]rule

Certain CPUs are vulnerable to an exploit against a common wide industry wide performance optimization known as Speculative Store Bypass (SSB). In such cases, recent stores to the same memory location cannot always be observed by later loads during speculative execution. However, such stores are unlikely and thus they can be detected prior to instruction retirement at the end of a particular speculation execution window. Since Linux Kernel 4.17 you can check the SSB mitigation state with the following command: cat /sys/devices/system/cpu/vulnerabilities/spec_store_bypass Select the appropriate SSB state by adding the argument spec_store_bypass_disable=seccomp to the default GRUB 2 command line for the Linux operating system. Configure the default Grub2 kernel command line to contain spec_store_bypass_disable=seccomp as follows:

# grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) spec_store_bypass_disable=seccomp"

Warning:  Disabling Speculative Store Bypass may impact performance of the system.
Rationale:

In vulnerable processsors, the speculatively forwarded store can be used in a cache side channel attack. An example of this is reading memory to which the attacker does not directly have access, for example inside the sandboxed code.

Severity:  medium

References:  BP28(R8)

Enforce Spectre v2 mitigation   [ref]rule

Spectre V2 is an indirect branch poisoning attack that can lead to data leakage. An exploit for Spectre V2 tricks the indirect branch predictor into executing code from a future indirect branch chosen by the attacker, even if the privilege level is different. Since Linux Kernel 4.15 you can check the Spectre V2 mitigation state with the following command: cat /sys/devices/system/cpu/vulnerabilities/spectre_v2 Enforce the Spectre V2 mitigation by adding the argument spectre_v2=on to the default GRUB 2 command line for the Linux operating system. Configure the default Grub2 kernel command line to contain spectre_v2=on) as follows:

# grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) spectre_v2=on)"

Rationale:

The Spectre V2 vulnerability allows an attacker to read memory that he should not have access to.

Severity:  high

References:  BP28(R8)

Kernel Configuration   [ref]group

Contains rules that check the kernel configuration that was used to build it.

contains 41 rules

Do not allow ACPI methods to be inserted/replaced at run time   [ref]rule

This debug facility allows ACPI AML methods to be inserted and/or replaced without rebooting the system. This configuration is available from kernel 3.0. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_ACPI_CUSTOM_METHOD, run the following command: grep CONFIG_ACPI_CUSTOM_METHOD /boot/config-* Configs with value 'n' are not explicitly set in the file, so either commented lines or no lines should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

Enabling this feature allows arbitrary kernel memory to be written to by root (uid=0) users, allowing them to bypass certain security measures

Severity:  low

References:  BP28(R15)

Disable kernel support for MISC binaries   [ref]rule

Enabling CONFIG_BINFMT_MISC makes it possible to plug wrapper-driven binary formats into the kernel. This is specially useful for programs that need an interpreter to run like Java, Python and DOS emulators. Once you have registered such a binary class with the kernel, you can start one of those programs simply by typing in its name at a shell prompt. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_BINFMT_MISC, run the following command: grep CONFIG_BINFMT_MISC /boot/config-* Configs with value 'n' are not explicitly set in the file, so either commented lines or no lines should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

This disables arbitrary binary format support and helps reduce attack surface.

Severity:  medium

References:  BP28(R23)

Enable support for BUG()   [ref]rule

Disabling this option eliminates support for BUG and WARN, reducing the size of your kernel image and potentially quietly ignoring numerous fatal conditions. You should only consider disabling this option for embedded systems with no facilities for reporting errors. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_BUG, run the following command: grep CONFIG_BUG /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

Not setting this variable may hide a number of critical errors.

Severity:  medium

References:  BP28(R19)

Disable compatibility with brk()   [ref]rule

Enabling compatiliby with brk() allows legacy binaries to run (i.e. those linked against libc5). But this compatibility comes at the cost of not being able to randomize the heap placement (ASLR). Unless legacy binaries need to run on the system, set CONFIG_COMPAT_BRK to "n". The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_COMPAT_BRK, run the following command: grep CONFIG_COMPAT_BRK /boot/config-* Configs with value 'n' are not explicitly set in the file, so either commented lines or no lines should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

Enabling compatibility with brk() disables support for ASLR.

Severity:  medium

References:  BP28(R17)

Disable the 32-bit vDSO   [ref]rule

Certain buggy versions of glibc (2.3.3) will crash if they are presented with a 32-bit vDSO that is not mapped at the address indicated in its segment table. Setting CONFIG_COMPAT_VDSO to y turns off the 32-bit VDSO and works aroud the glibc bug. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_COMPAT_VDSO, run the following command: grep CONFIG_COMPAT_VDSO /boot/config-* Configs with value 'n' are not explicitly set in the file, so either commented lines or no lines should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

Enabling VDSO compatibility hurts performance and disables ASLR.

Severity:  low

References:  BP28(R15)

Enable checks on credential management   [ref]rule

Enable this to turn on some debug checking for credential management. The additional code keeps track of the number of pointers from task_structs to any given cred struct, and checks to see that this number never exceeds the usage count of the cred struct. Furthermore, if SELinux is enabled, this also checks that the security pointer in the cred struct is never seen to be invalid. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_DEBUG_CREDENTIALS, run the following command: grep CONFIG_DEBUG_CREDENTIALS /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

This adds sanity checks and validations to credential data structures.

Severity:  low

References:  BP28(R16)

Disable kernel debugfs   [ref]rule

debugfs is a virtual file system that kernel developers use to put debugging files into. Enable this option to be able to read and write to these files. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_DEBUG_FS, run the following command: grep CONFIG_DEBUG_FS /boot/config-* Configs with value 'n' are not explicitly set in the file, so either commented lines or no lines should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

To reduce the attack surface, this file system should be disabled if not in use.

Severity:  low

References:  BP28(R15)

Enable checks on linked list manipulation   [ref]rule

Enable this to turn on extended checks in the linked-list walking routines. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_DEBUG_LIST, run the following command: grep CONFIG_DEBUG_LIST /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

This add sanity checks to manipulation of linked lists structures in the kernel and may prevent exploits such as CVE-2017-1661, where a race condition and simultaneos operations caused a list to corrupt.

Severity:  low

References:  BP28(R16)

Enable checks on notifier call chains   [ref]rule

Enable this to turn on sanity checking for notifier call chains. This is most useful for kernel developers to make sure that modules properly unregister themselves from notifier chains. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_DEBUG_NOTIFIERS, run the following command: grep CONFIG_DEBUG_NOTIFIERS /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

This provides validation of notifier chains, it checks whether the notifiers are from the kernel or a module that is still loaded prior to being invoked.

Severity:  low

References:  BP28(R16)

Enable checks on scatter-gather (SG) table operations   [ref]rule

Scatter-gather tables are mechanism used for high performance I/O on DMA devices. Enable this to turn on checks on scatter-gather tables. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_DEBUG_SG, run the following command: grep CONFIG_DEBUG_SG /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

This can help find problems with drivers that do not properly initialize their SG tables.

Severity:  low

References:  BP28(R16)

Configure low address space to protect from user allocation   [ref]rule

This is the portion of low virtual memory which should be protected from userspace allocation. This configuration is available from kernel 3.14, but may be available if backported by distros. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_DEFAULT_MMAP_MIN_ADDR, run the following command: grep CONFIG_DEFAULT_MMAP_MIN_ADDR /boot/config-* For each kernel installed, a line with value "65536" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

Keeping a user from writing to low pages can help reduce the impact of kernel NULL pointer bugs.

Severity:  medium

References:  BP28(R25)

Disable /dev/kmem virtual device support   [ref]rule

Disable support for the /dev/kmem device. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_DEVKMEM, run the following command: grep CONFIG_DEVKMEM /boot/config-* Configs with value 'n' are not explicitly set in the file, so either commented lines or no lines should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

The /dev/kmem device is rarely used, but can be used for certain kind of kernel debugging operations.

Severity:  low

References:  BP28(R15)

Disable hibernation   [ref]rule

Enable the suspend to disk (STD) functionality, which is usually called "hibernation" in user interfaces. STD checkpoints the system and powers it off; and restores that checkpoint on reboot. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_HIBERNATION, run the following command: grep CONFIG_HIBERNATION /boot/config-* Configs with value 'n' are not explicitly set in the file, so either commented lines or no lines should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

Suspending to disk allows one to replace the running kernel.

Severity:  medium

References:  BP28(R23)

Disable IA32 emulation   [ref]rule

Disables support for legacy 32-bit programs under a 64-bit kernel. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_IA32_EMULATION, run the following command: grep CONFIG_IA32_EMULATION /boot/config-* Configs with value 'n' are not explicitly set in the file, so either commented lines or no lines should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Warning:  Only disable support for 32-bit programs if you are sure you don't need any 32-bit program.
Rationale:

Disabling 32-bit backwards compatibility helps reduce the attack surface.

Severity:  medium

References:  BP28(R25)

Disable kexec system call   [ref]rule

kexec is a system call that implements the ability to shutdown your current kernel, and to start another kernel. It is like a reboot but it is independent of the system firmware. And like a reboot you can start any kernel with it, not just Linux. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_KEXEC, run the following command: grep CONFIG_KEXEC /boot/config-* Configs with value 'n' are not explicitly set in the file, so either commented lines or no lines should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

Prohibits the execution of a new kernel image after reboot.

Severity:  low

References:  BP28(R23)

Disable legacy (BSD) PTY support   [ref]rule

Disable the Linux traditional BSD-like terminal names /dev/ptyxx for masters and /dev/ttyxx for slaves of pseudo terminals, and use only the modern ptys (devpts) interface. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_LEGACY_PTYS, run the following command: grep CONFIG_LEGACY_PTYS /boot/config-* Configs with value 'n' are not explicitly set in the file, so either commented lines or no lines should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

The legacy scheme has a number of security problems.

Severity:  medium

References:  BP28(R23)

Enable module signature verification   [ref]rule

Check modules for valid signatures upon load. Note that this option adds the OpenSSL development packages as a kernel build dependency so that the signing tool can use its crypto library. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_MODULE_SIG, run the following command: grep CONFIG_MODULE_SIG /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

Loaded modules must be signed.

Severity:  medium

References:  BP28(R18)

Enable automatic signing of all modules   [ref]rule

Sign all modules during make modules_install. Without this option, modules must be signed manually, using the scripts/sign-file tool. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_MODULE_SIG_ALL, run the following command: grep CONFIG_MODULE_SIG_ALL /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

This ensures the modules are signed during install process.

Severity:  medium

References:  BP28(R18)

Require modules to be validly signed   [ref]rule

Reject unsigned modules or signed modules with an unknown key. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_MODULE_SIG_FORCE, run the following command: grep CONFIG_MODULE_SIG_FORCE /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

Prevent loading modules that are unsigned or signed with an unknown key.

Severity:  medium

References:  BP28(R18)

Specify the hash to use when signing modules   [ref]rule

This configures the kernel to build and sign modules using sha512 as the hash function. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_MODULE_SIG_HASH, run the following command: grep CONFIG_MODULE_SIG_HASH /boot/config-* For each kernel installed, a line with value "sha512" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

Use of strong hash function is important to secure the module against counterfeit signatures.

Severity:  medium

References:  BP28(R18)

Specify module signing key to use   [ref]rule

Setting this option to something other than its default of certs/signing_key.pem will disable the autogeneration of signing keys and allow the kernel modules to be signed with a key of your choosing. The string provided should identify a file containing both a private key and its corresponding X.509 certificate in PEM form, or — on systems where the OpenSSL ENGINE_pkcs11 is functional — a PKCS#11 URI as defined by RFC7512. In the latter case, the PKCS#11 URI should reference both a certificate and a private key. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_MODULE_SIG_KEY, run the following command: grep CONFIG_MODULE_SIG_KEY /boot/config-* For each kernel installed, a line with value "certs/signing_key.pem" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

A key and certificate is required to sign the built modules.

Severity:  medium

References:  BP28(R18)

Sign kernel modules with SHA-512   [ref]rule

This configures the kernel to build and sign modules using SHA512 as the hash function. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_MODULE_SIG_SHA512, run the following command: grep CONFIG_MODULE_SIG_SHA512 /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

Use of strong hash function is important to secure the module against counterfeit signatures.

Severity:  medium

References:  BP28(R18)

Enable poison without sanity check   [ref]rule

Skip the sanity checking on alloc, only fill the pages with poison on free. This reduces some of the overhead of the poisoning feature. This configuration is available from kernel 4.6. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_PAGE_POISONING_NO_SANITY, run the following command: grep CONFIG_PAGE_POISONING_NO_SANITY /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

This configuration helps alleviates the performance impact of poisonining.

Severity:  medium

References:  BP28(R17)

Use zero for poisoning instead of debugging value   [ref]rule

Instead of using the existing poison value, fill the pages with zeros. This makes it harder to detect when errors are occurring due to sanitization but the zeroing at free means that it is no longer necessary to write zeros when GFP_ZERO is used on allocation. This configuration is available from kernel 4.19. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_PAGE_POISONING_ZERO, run the following command: grep CONFIG_PAGE_POISONING_ZERO /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

This configuration helps alleviates the performance impact of poisonining.

Severity:  medium

References:  BP28(R17)

Remove the kernel mapping in user mode   [ref]rule

This feature reduces the number of hardware side channels by ensuring that the majority of kernel addresses are not mapped into userspace. This configuration is available from kernel 4.15, but may be available if backported by distros. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_PAGE_TABLE_ISOLATION, run the following command: grep CONFIG_PAGE_TABLE_ISOLATION /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

This is a countermeasure to the Meltdown attack.

Severity:  high

References:  BP28(R25)

Kernel panic oops   [ref]rule

Enable the kernel to panic when it oopses. This has the same effect as setting oops=panic on the kernel command line. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_PANIC_ON_OOPS, run the following command: grep CONFIG_PANIC_ON_OOPS /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

This feature ensures that the kernel does not do anything erroneous after an oops which could result in data corruption or other issues.

Severity:  medium

References:  BP28(R19)

Kernel panic timeout   [ref]rule

Set the timeout value (in seconds) until a reboot occurs when the kernel panics. A timeout of 0 configures the system to wait forever. With a timeout value greater than 0, the system will wait the specified amount of seconds before rebooting. While a timeout value less than 0 makes the system reboot immediately. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_PANIC_TIMEOUT, run the following command: grep CONFIG_PANIC_TIMEOUT /boot/config-* For each kernel installed, a line with value "0" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

This is required to enable protection against Spectre v2.

Severity:  medium

References:  BP28(R19)

Disable support for /proc/kkcore   [ref]rule

Provides a virtual ELF core file of the live kernel. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_PROC_KCORE, run the following command: grep CONFIG_PROC_KCORE /boot/config-* Configs with value 'n' are not explicitly set in the file, so either commented lines or no lines should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

This feature exposes the memory to the userspace and can assist an attacker in discovering attack vectors.

Severity:  low

References:  BP28(R15)

Randomize the address of the kernel image (KASLR)   [ref]rule

In support of Kernel Address Space Layout Randomization (KASLR), this randomizes the physical address at which the kernel image is decompressed and the virtual address where the kernel image is mapped. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_RANDOMIZE_BASE, run the following command: grep CONFIG_RANDOMIZE_BASE /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

An unpredictable kernel address makes it more difficult to succeed with exploits that rely on knowledge of the location of kernel code internals.

Severity:  medium

References:  BP28(R25), BP28(R27)

Randomize the kernel memory sections   [ref]rule

Randomizes the base virtual address of kernel memory sections (physical memory mapping, vmalloc & vmemmap). This configuration is available from kernel 4.8, but may be available if backported by distros. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_RANDOMIZE_MEMORY, run the following command: grep CONFIG_RANDOMIZE_MEMORY /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

This security feature makes exploits relying on predictable memory locations less reliable.

Severity:  medium

References:  BP28(R25)

Avoid speculative indirect branches in kernel   [ref]rule

Compile kernel with the retpoline compiler options to guard against kernel-to-user data leaks by avoiding speculative indirect branches. Requires a compiler with -mindirect-branch=thunk-extern support for full protection. The kernel may run slower. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_RETPOLINE, run the following command: grep CONFIG_RETPOLINE /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

This is required to enable protection against Spectre v2.

Severity:  medium

References:  BP28(R15)

Enable seccomp to safely compute untrusted bytecode   [ref]rule

This kernel feature is useful for number crunching applications that may need to compute untrusted bytecode during their execution. By using pipes or other transports made available to the process as file descriptors supporting the read/write syscalls, it's possible to isolate those applications in their own address space using seccomp. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_SECCOMP, run the following command: grep CONFIG_SECCOMP /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

seccomp enables the ability to filter system calls made by an application, effectively isolating the system's resources from it.

Severity:  medium

References:  BP28(R20)

Enable use of Berkeley Packet Filter with seccomp   [ref]rule

Enable tasks to build secure computing environments defined in terms of Berkeley Packet Filter programs which implement task-defined system call filtering polices. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_SECCOMP_FILTER, run the following command: grep CONFIG_SECCOMP_FILTER /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

Use of BPF filters allows for expressive filtering of system calls using a filter program language with a long history of being exposed to userland.

Severity:  medium

References:  BP28(R20)

Enable different security models   [ref]rule

This allows you to choose different security modules to be configured into your kernel. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_SECURITY, run the following command: grep CONFIG_SECURITY /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

This is enables kernel security primitives required by the LSM framework.

Severity:  medium

References:  BP28(R20)

Restrict unprivileged access to the kernel syslog   [ref]rule

Enforce restrictions on unprivileged users reading the kernel syslog via dmesg(8). The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_SECURITY_DMESG_RESTRICT, run the following command: grep CONFIG_SECURITY_DMESG_RESTRICT /boot/config-* Configs with value 'n' are not explicitly set in the file, so either commented lines or no lines should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

Prevents unprivileged users from retrieving kernel addresses with dmesg.

Severity:  medium

References:  BP28(R15)

Disable mutable hooks   [ref]rule

Ensure kernel structures associated with LSMs are always mapped as read-only after system boot. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_SECURITY_WRITABLE_HOOKS, run the following command: grep CONFIG_SECURITY_WRITABLE_HOOKS /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

If CONFIG_SECURITY_WRITABLE_HOOKS is enabled, then hooks can be loaded at runtime and being able to manipulate hooks is a way to bypass all LSMs.

Severity:  medium

References:  BP28(R20)

Enable Yama support   [ref]rule

This enables support for LSM module Yama, which extends DAC support with additional system-wide security settings beyond regular Linux discretionary access controls. The module will limit the use of the system call ptrace(). The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_SECURITY_YAMA, run the following command: grep CONFIG_SECURITY_YAMA /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

Unrestricted usage of ptrace allows compromised binaries to run ptrace on another processes of the user.

Severity:  medium

References:  BP28(R20)

Enable SLUB debugging support   [ref]rule

SLUB has extensive debug support features and this allows the allocator validation checking to be enabled. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_SLUB_DEBUG, run the following command: grep CONFIG_SLUB_DEBUG /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

This activates the checking of the memory allocator structures and resets to zero the zones allocated when they are released.

Severity:  medium

References:  BP28(R17)

Enable TCP/IP syncookie support   [ref]rule

Normal TCP/IP networking is open to an attack known as SYN flooding. It is denial-of-service attack that prevents legitimate remote users from being able to connect to your computer during an ongoing attack. When enabled the TCP/IP stack will use a cryptographic challenge protocol known as SYN cookies to enable legitimate users to continue to connect, even when your machine is under attack. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_SYN_COOKIES, run the following command: grep CONFIG_SYN_COOKIES /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

SYN cookies provide protection against SYN flooding attacks.

Severity:  medium

References:  BP28(R22)

Unmap kernel when running in userspace (aka KAISER)   [ref]rule

Speculation attacks against some high-performance processors can be used to bypass MMU permission checks and leak kernel data to userspace. This can be defended against by unmapping the kernel when running in userspace, mapping it back in on exception entry via a trampoline page in the vector table. This configuration is available from kernel 4.16, but may be available if backported by distros. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_UNMAP_KERNEL_AT_EL0, run the following command: grep CONFIG_UNMAP_KERNEL_AT_EL0 /boot/config-* For each kernel installed, a line with value "y" should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

This is a countermeasure to the Meltdown attack.

Severity:  medium

References:  BP28(R27)

Disable x86 vsyscall emulation   [ref]rule

Disabling it is roughly equivalent to booting with vsyscall=none, except that it will also disable the helpful warning if a program tries to use a vsyscall. With this option set to N, offending programs will just segfault, citing addresses of the form 0xffffffffff600?00. This configuration is available from kernel 3.19. The configuration that was used to build kernel is available at /boot/config-*. To check the configuration value for CONFIG_X86_VSYSCALL_EMULATION, run the following command: grep CONFIG_X86_VSYSCALL_EMULATION /boot/config-* Configs with value 'n' are not explicitly set in the file, so either commented lines or no lines should be returned.

Warning:  There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale:

The vsyscall table is no longer required and is a potential source of ROP gadgets.

Severity:  low

References:  BP28(R15)

Configure Syslog   [ref]group

The syslog service has been the default Unix logging mechanism for many years. It has a number of downsides, including inconsistent log format, lack of authentication for received messages, and lack of authentication, encryption, or reliable transport for messages sent over a network. However, due to its long history, syslog is a de facto standard which is supported by almost all Unix applications.

In Red Hat Enterprise Linux CoreOS 4, rsyslog has replaced ksyslogd as the syslog daemon of choice, and it includes some additional security features such as reliable, connection-oriented (i.e. TCP) transmission of logs, the option to log to database formats, and the encryption of log data en route to a central logging server. This section discusses how to configure rsyslog for best effect, and how to use tools provided with the system to maintain and monitor logs.

contains 7 rules

Ensure Proper Configuration of Log Files   [ref]group

The file /etc/rsyslog.conf controls where log message are written. These are controlled by lines called rules, which consist of a selector and an action. These rules are often customized depending on the role of the system, the requirements of the environment, and whatever may enable the administrator to most effectively make use of log data. The default rules in Red Hat Enterprise Linux CoreOS 4 are:

*.info;mail.none;authpriv.none;cron.none                /var/log/messages
authpriv.*                                              /var/log/secure
mail.*                                                  -/var/log/maillog
cron.*                                                  /var/log/cron
*.emerg                                                 *
uucp,news.crit                                          /var/log/spooler
local7.*                                                /var/log/boot.log
See the man page rsyslog.conf(5) for more information. Note that the rsyslog daemon can be configured to use a timestamp format that some log processing programs may not understand. If this occurs, edit the file /etc/rsyslog.conf and add or edit the following line:
$ ActionFileDefaultTemplate RSYSLOG_TraditionalFileFormat

contains 3 rules

Ensure Log Files Are Owned By Appropriate Group   [ref]rule

The group-owner of all log files written by rsyslog should be root. These log files are determined by the second part of each Rule line in /etc/rsyslog.conf and typically all appear in /var/log. For each log file LOGFILE referenced in /etc/rsyslog.conf, run the following command to inspect the file's group owner:

$ ls -l LOGFILE
If the owner is not root, run the following command to correct this:
$ sudo chgrp root LOGFILE

Rationale:

The log files generated by rsyslog contain valuable information regarding system configuration, user authentication, and other such information. Log files should be protected from unauthorized access.

Severity:  medium

Ensure Log Files Are Owned By Appropriate User   [ref]rule

The owner of all log files written by rsyslog should be root. These log files are determined by the second part of each Rule line in /etc/rsyslog.conf and typically all appear in /var/log. For each log file LOGFILE referenced in /etc/rsyslog.conf, run the following command to inspect the file's owner:

$ ls -l LOGFILE
If the owner is not root, run the following command to correct this:
$ sudo chown root LOGFILE

Rationale:

The log files generated by rsyslog contain valuable information regarding system configuration, user authentication, and other such information. Log files should be protected from unauthorized access.

Severity:  medium

Ensure System Log Files Have Correct Permissions   [ref]rule

The file permissions for all log files written by rsyslog should be set to 640, or more restrictive. These log files are determined by the second part of each Rule line in /etc/rsyslog.conf and typically all appear in /var/log. For each log file LOGFILE referenced in /etc/rsyslog.conf, run the following command to inspect the file's permissions:

$ ls -l LOGFILE
If the permissions are not 640 or more restrictive, run the following command to correct this:
$ sudo chmod 640 LOGFILE
"

Rationale:

Log files can contain valuable information regarding system configuration. If the system log files are not protected unauthorized users could change the logged data, eliminating their forensic value.

Severity:  medium

Ensure All Logs are Rotated by logrotate   [ref]group

Edit the file /etc/logrotate.d/syslog. Find the first line, which should look like this (wrapped for clarity):

/var/log/messages /var/log/secure /var/log/maillog /var/log/spooler \
  /var/log/boot.log /var/log/cron {
Edit this line so that it contains a one-space-separated listing of each log file referenced in /etc/rsyslog.conf.

All logs in use on a system must be rotated regularly, or the log files will consume disk space over time, eventually interfering with system operation. The file /etc/logrotate.d/syslog is the configuration file used by the logrotate program to maintain all log files written by syslog. By default, it rotates logs weekly and stores four archival copies of each log. These settings can be modified by editing /etc/logrotate.conf, but the defaults are sufficient for purposes of this guide.

Note that logrotate is run nightly by the cron job /etc/cron.daily/logrotate. If particularly active logs need to be rotated more often than once a day, some other mechanism must be used.

contains 3 rules

Ensure logrotate is Installed   [ref]rule

logrotate is installed by default. The logrotate package can be installed with the following command:

Rationale:

The logrotate package provides the logrotate services.

Severity:  medium

Ensure Logrotate Runs Periodically   [ref]rule

The logrotate utility allows for the automatic rotation of log files. The frequency of rotation is specified in /etc/logrotate.conf, which triggers a cron task or a timer. To configure logrotate to run daily, add or correct the following line in /etc/logrotate.conf:

# rotate log files frequency
daily

Rationale:

Log files that are not properly rotated run the risk of growing so large that they fill up the /var/log partition. Valuable logging information could be lost if the /var/log partition becomes full.

Severity:  medium

Remediation script:   (show)

Complexity:low
Disruption:low
Reboot:true
Strategy:restrict
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,{{ %23%20see%20%22man%20logrotate%22%20for%20details%0A%23%20rotate%20log%20files%20daily%0Adaily%0A%0A%23%20keep%204%20weeks%20worth%20of%20backlogs%0Arotate%2030%0A%0A%23%20create%20new%20%28empty%29%20log%20files%20after%20rotating%20old%20ones%0Acreate%0A%0A%23%20use%20date%20as%20a%20suffix%20of%20the%20rotated%20file%0Adateext%0A%0A%23%20uncomment%20this%20if%20you%20want%20your%20log%20files%20compressed%0A%23compress%0A%0A%23%20RPM%20packages%20drop%20log%20rotation%20information%20into%20this%20directory%0Ainclude%20/etc/logrotate.d%0A%0A%23%20system-specific%20logs%20may%20be%20also%20be%20configured%20here. }}
        mode: 0644
        path: /etc/logrotate.conf
        overwrite: true

Enable logrotate Timer   [ref]rule

The logrotate timer can be enabled with the following command:

$ sudo systemctl enable logrotate.timer

Rationale:

Log files that are not properly rotated run the risk of growing so large that they fill up the /var/log partition. Valuable logging information could be lost if the /var/log partition becomes full.

Severity:  medium

Rsyslog Logs Sent To Remote Host   [ref]group

If system logs are to be useful in detecting malicious activities, it is necessary to send logs to a remote server. An intruder who has compromised the root account on a system may delete the log entries which indicate that the system was attacked before they are seen by an administrator.

However, it is recommended that logs be stored on the local host in addition to being sent to the loghost, especially if rsyslog has been configured to use the UDP protocol to send messages over a network. UDP does not guarantee reliable delivery, and moderately busy sites will lose log messages occasionally, especially in periods of high traffic which may be the result of an attack. In addition, remote rsyslog messages are not authenticated in any way by default, so it is easy for an attacker to introduce spurious messages to the central log server. Also, some problems cause loss of network connectivity, which will prevent the sending of messages to the central server. For all of these reasons, it is better to store log messages both centrally and on each host, so that they can be correlated if necessary.

contains 1 rule

Ensure Logs Sent To Remote Host   [ref]rule

To configure rsyslog to send logs to a remote log server, open /etc/rsyslog.conf and read and understand the last section of the file, which describes the multiple directives necessary to activate remote logging. Along with these other directives, the system can be configured to forward its logs to a particular log server by adding or correcting one of the following lines, substituting logcollector appropriately. The choice of protocol depends on the environment of the system; although TCP and RELP provide more reliable message delivery, they may not be supported in all environments.
To use UDP for log message delivery:

*.* @logcollector

To use TCP for log message delivery:
*.* @@logcollector

To use RELP for log message delivery:
*.* :omrelp:logcollector

There must be a resolvable DNS CNAME or Alias record set to "logcollector" for logs to be sent correctly to the centralized logging utility.

Warning:  It is important to configure queues in case the client is sending log messages to a remote server. If queues are not configured, the system will stop functioning when the connection to the remote server is not available. Please consult Rsyslog documentation for more information about configuration of queues. The example configuration which should go into /etc/rsyslog.conf can look like the following lines:
$ActionQueueType LinkedList
$ActionQueueFileName queuefilename
$ActionQueueMaxDiskSpace 1g
$ActionQueueSaveOnShutdown on
$ActionResumeRetryCount -1
Rationale:

A log server (loghost) receives syslog messages from one or more systems. This data can be used as an additional log source in the event a system is compromised and its local logs are suspect. Forwarding log messages to a remote loghost also provides system administrators with a centralized place to view the status of multiple hosts within the enterprise.

Severity:  medium

Network Configuration and Firewalls   [ref]group

Most systems must be connected to a network of some sort, and this brings with it the substantial risk of network attack. This section discusses the security impact of decisions about networking which must be made when configuring a system.

This section also discusses firewalls, network access controls, and other network security frameworks, which allow system-level rules to be written that can limit an attackers' ability to connect to your system. These rules can specify that network traffic should be allowed or denied from certain IP addresses, hosts, and networks. The rules can also specify which of the system's network services are available to particular hosts or networks.

contains 23 rules

IPv6   [ref]group

The system includes support for Internet Protocol version 6. A major and often-mentioned improvement over IPv4 is its enormous increase in the number of available addresses. Another important feature is its support for automatic configuration of many network settings.

contains 4 rules

Configure IPv6 Settings if Necessary   [ref]group

A major feature of IPv6 is the extent to which systems implementing it can automatically configure their networking devices using information from the network. From a security perspective, manually configuring important configuration information is preferable to accepting it from the network in an unauthenticated fashion.

contains 4 rules

Disable Accepting ICMP Redirects for All IPv6 Interfaces   [ref]rule

To set the runtime status of the net.ipv6.conf.all.accept_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv6.conf.all.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv6.conf.all.accept_redirects = 0

Rationale:

An illicit ICMP redirect message could result in a man-in-the-middle attack.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,net.ipv6.conf.all.accept_redirects%3D0%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_net_ipv6_conf_all_accept_redirects.conf
        overwrite: true

Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv6 Interfaces   [ref]rule

To set the runtime status of the net.ipv6.conf.all.accept_source_route kernel parameter, run the following command:

$ sudo sysctl -w net.ipv6.conf.all.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv6.conf.all.accept_source_route = 0

Rationale:

Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routerd traffic, such as when IPv6 forwarding is enabled and the system is functioning as a router.

Accepting source-routed packets in the IPv6 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,net.ipv6.conf.all.accept_source_route%3D0%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_net_ipv6_conf_all_accept_source_route.conf
        overwrite: true

Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv6 Interfaces   [ref]rule

To set the runtime status of the net.ipv6.conf.default.accept_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv6.conf.default.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv6.conf.default.accept_redirects = 0

Rationale:

An illicit ICMP redirect message could result in a man-in-the-middle attack.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,net.ipv6.conf.default.accept_redirects%20%3D%200%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_net_ipv6_conf_default_accept_redirects.conf
        overwrite: true

Disable Kernel Parameter for Accepting Source-Routed Packets on IPv6 Interfaces by Default   [ref]rule

To set the runtime status of the net.ipv6.conf.default.accept_source_route kernel parameter, run the following command:

$ sudo sysctl -w net.ipv6.conf.default.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv6.conf.default.accept_source_route = 0

Rationale:

Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routerd traffic, such as when IPv6 forwarding is enabled and the system is functioning as a router. Accepting source-routed packets in the IPv6 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,net.ipv6.conf.default.accept_source_route%3D0%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_net_ipv6_conf_default_accept_source_route.conf
        overwrite: true

Kernel Parameters Which Affect Networking   [ref]group

The sysctl utility is used to set parameters which affect the operation of the Linux kernel. Kernel parameters which affect networking and have security implications are described here.

contains 19 rules

Network Related Kernel Runtime Parameters for Hosts and Routers   [ref]group

Certain kernel parameters should be set for systems which are acting as either hosts or routers to improve the system's ability defend against certain types of IPv4 protocol attacks.

contains 16 rules

Disable Accepting Packets Routed Between Local Interfaces   [ref]rule

To set the runtime status of the net.ipv4.conf.all.accept_local kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.accept_local=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.all.accept_local = 0

Rationale:

Configure net.ipv4.conf.all.accept_local=0 to consider as invalid the packets received from outside whose source is the 127.0.0.0/8 address block. In combination with suitable routing, this can be used to direct packets between two local interfaces over the wire and have them accepted properly.

Severity:  medium

References:  BP28(R12)

Disable Accepting ICMP Redirects for All IPv4 Interfaces   [ref]rule

To set the runtime status of the net.ipv4.conf.all.accept_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.all.accept_redirects = 0

Rationale:

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack.
This feature of the IPv4 protocol has few legitimate uses. It should be disabled unless absolutely required."

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,net.ipv4.conf.all.accept_redirects%3D0%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_all_accept_redirects.conf
        overwrite: true

Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv4 Interfaces   [ref]rule

To set the runtime status of the net.ipv4.conf.all.accept_source_route kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.all.accept_source_route = 0

Rationale:

Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routerd traffic, such as when IPv4 forwarding is enabled and the system is functioning as a router.

Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,net.ipv4.conf.all.accept_source_route%3D0%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_all_accept_source_route.conf
        overwrite: true

Configure ARP filtering for All IPv4 Interfaces   [ref]rule

To set the runtime status of the net.ipv4.conf.all.arp_filter kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.arp_filter=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.all.arp_filter = 0

Warning:  This behaviour may cause problems to system on a high availability or load balancing configuration.
Rationale:

Prevents the Linux Kernel from handling the ARP table globally. By default, the kernel may respond to an ARP request from a certain interface with information from another interface.

Severity:  medium

References:  BP28(R12)

Configure Response Mode of ARP Requests for All IPv4 Interfaces   [ref]rule

To set the runtime status of the net.ipv4.conf.all.arp_ignore kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.arp_ignore=2
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.all.arp_ignore = 2

Warning:  The ARP response mode may impact behaviour of workloads and firewalls on the system.
Rationale:

Avoids ARP Flux on system that have more than one interface on the same subnet.

Severity:  medium

References:  BP28(R12)

Prevent Routing External Traffic to Local Loopback on All IPv4 Interfaces   [ref]rule

To set the runtime status of the net.ipv4.conf.all.route_localnet kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.route_localnet=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.all.route_localnet = 0

Rationale:

Refuse the routing of packets whose source or destination address is the local loopback. This prohibits the use of network 127/8 for local routing purposes. Enabling route_localnet can expose applications listening on localhost to external traffic.

Severity:  medium

References:  BP28(R12)

Enable Kernel Parameter to Use Reverse Path Filtering on all IPv4 Interfaces   [ref]rule

To set the runtime status of the net.ipv4.conf.all.rp_filter kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.rp_filter=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.all.rp_filter = 1

Rationale:

Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface they were received on. It should not be used on systems which are routers for complicated networks, but is helpful for end hosts and routers serving small networks.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,net.ipv4.conf.all.rp_filter%3D1%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_all_rp_filter.conf
        overwrite: true

Disable Kernel Parameter for Accepting Secure ICMP Redirects on all IPv4 Interfaces   [ref]rule

To set the runtime status of the net.ipv4.conf.all.secure_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.secure_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.all.secure_redirects = 0

Rationale:

Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,net.ipv4.conf.all.secure_redirects%3D0%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_all_secure_redirects.conf
        overwrite: true

Configure Sending and Accepting Shared Media Redirects for All IPv4 Interfaces   [ref]rule

To set the runtime status of the net.ipv4.conf.all.shared_media kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.shared_media=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.all.shared_media = 0

Rationale:

This setting should be aligned with net.ipv4.conf.all.secure_redirects because it overrides it. If shared_media is enabled for an interface secure_redirects will be enabled too.

Severity:  medium

References:  BP28(R12)

Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv4 Interfaces   [ref]rule

To set the runtime status of the net.ipv4.conf.default.accept_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.default.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.default.accept_redirects = 0

Rationale:

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack.
This feature of the IPv4 protocol has few legitimate uses. It should be disabled unless absolutely required.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,net.ipv4.conf.default.accept_redirects%3D0%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_default_accept_redirects.conf
        overwrite: true

Disable Kernel Parameter for Accepting Source-Routed Packets on IPv4 Interfaces by Default   [ref]rule

To set the runtime status of the net.ipv4.conf.default.accept_source_route kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.default.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.default.accept_source_route = 0

Rationale:

Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures.
Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required, such as when IPv4 forwarding is enabled and the system is legitimately functioning as a router.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,net.ipv4.conf.default.accept_source_route%3D0%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_default_accept_source_route.conf
        overwrite: true

Enable Kernel Parameter to Use Reverse Path Filtering on all IPv4 Interfaces by Default   [ref]rule

To set the runtime status of the net.ipv4.conf.default.rp_filter kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.default.rp_filter=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.default.rp_filter = 1

Rationale:

Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface they were received on. It should not be used on systems which are routers for complicated networks, but is helpful for end hosts and routers serving small networks.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,net.ipv4.conf.default.rp_filter%3D1%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_default_rp_filter.conf
        overwrite: true

Configure Kernel Parameter for Accepting Secure Redirects By Default   [ref]rule

To set the runtime status of the net.ipv4.conf.default.secure_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.default.secure_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.default.secure_redirects = 0

Rationale:

Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,net.ipv4.conf.default.secure_redirects%3D0%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_default_secure_redirects.conf
        overwrite: true

Configure Sending and Accepting Shared Media Redirects by Default   [ref]rule

To set the runtime status of the net.ipv4.conf.default.shared_media kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.default.shared_media=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.default.shared_media = 0

Rationale:

This setting should be aligned with net.ipv4.conf.default.secure_redirects because it overrides it. If shared_media is enabled for an interface secure_redirects will be enabled too.

Severity:  medium

References:  BP28(R12)

Enable Kernel Parameter to Ignore Bogus ICMP Error Responses on IPv4 Interfaces   [ref]rule

To set the runtime status of the net.ipv4.icmp_ignore_bogus_error_responses kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.icmp_ignore_bogus_error_responses=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.icmp_ignore_bogus_error_responses = 1

Rationale:

Ignoring bogus ICMP error responses reduces log size, although some activity would not be logged.

Severity:  unknown

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,net.ipv4.icmp_ignore_bogus_error_responses%3D1%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_net_ipv4_icmp_ignore_bogus_error_responses.conf
        overwrite: true

Enable Kernel Parameter to Use TCP Syncookies on Network Interfaces   [ref]rule

To set the runtime status of the net.ipv4.tcp_syncookies kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.tcp_syncookies=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.tcp_syncookies = 1

Rationale:

A TCP SYN flood attack can cause a denial of service by filling a system's TCP connection table with connections in the SYN_RCVD state. Syncookies can be used to track a connection when a subsequent ACK is received, verifying the initiator is attempting a valid connection and is not a flood source. This feature is activated when a flood condition is detected, and enables the system to continue servicing valid connection requests.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,net.ipv4.tcp_syncookies%3D1%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_net_ipv4_tcp_syncookies.conf
        overwrite: true

Network Parameters for Hosts Only   [ref]group

If the system is not going to be used as a router, then setting certain kernel parameters ensure that the host will not perform routing of network traffic.

contains 3 rules

Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces   [ref]rule

To set the runtime status of the net.ipv4.conf.all.send_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.send_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.all.send_redirects = 0

Rationale:

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table possibly revealing portions of the network topology.
The ability to send ICMP redirects is only appropriate for systems acting as routers.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,net.ipv4.conf.all.send_redirects%3D0%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_all_send_redirects.conf
        overwrite: true

Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces by Default   [ref]rule

To set the runtime status of the net.ipv4.conf.default.send_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.default.send_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.conf.default.send_redirects = 0

Rationale:

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table possibly revealing portions of the network topology.
The ability to send ICMP redirects is only appropriate for systems acting as routers.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,net.ipv4.conf.default.send_redirects%3D0%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_net_ipv4_conf_default_send_redirects.conf
        overwrite: true

Disable Kernel Parameter for IP Forwarding on IPv4 Interfaces   [ref]rule

To set the runtime status of the net.ipv4.ip_forward kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.ip_forward=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.ipv4.ip_forward = 0

Warning:  Certain technologies such as virtual machines, containers, etc. rely on IPv4 forwarding to enable and use networking. Disabling IPv4 forwarding would cause those technologies to stop working. Therefore, this rule should not be used in profiles or benchmarks that target usage of IPv4 forwarding.
Rationale:

Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this capability is used when not required, system network information may be unnecessarily transmitted across the network.

Severity:  medium

File Permissions and Masks   [ref]group

Traditional Unix security relies heavily on file and directory permissions to prevent unauthorized users from reading or modifying files to which they should not have access.

Several of the commands in this section search filesystems for files or directories with certain characteristics, and are intended to be run on every local partition on a given system. When the variable PART appears in one of the commands below, it means that the command is intended to be run repeatedly, with the name of each local partition substituted for PART in turn.

The following command prints a list of all xfs partitions on the local system, which is the default filesystem for Red Hat Enterprise Linux CoreOS 4 installations:

$ mount -t xfs | awk '{print $3}'
For any systems that use a different local filesystem type, modify this command as appropriate.

contains 29 rules

Verify Permissions on Important Files and Directories   [ref]group

Permissions for many files on a system must be set restrictively to ensure sensitive information is properly protected. This section discusses important permission restrictions which can be verified to ensure that no harmful discrepancies have arisen.

contains 10 rules
contains 6 rules

Verify User Who Owns gshadow File   [ref]rule

To properly set the owner of /etc/gshadow, run the command:

$ sudo chown root /etc/gshadow 

Rationale:

The /etc/gshadow file contains group password hashes. Protection of this file is critical for system security.

Severity:  medium

Verify User Who Owns shadow File   [ref]rule

To properly set the owner of /etc/shadow, run the command:

$ sudo chown root /etc/shadow 

Rationale:

The /etc/shadow file contains the list of local system accounts and stores password hashes. Protection of this file is critical for system security. Failure to give ownership of this file to root provides the designated owner with access to sensitive information which could weaken the system security posture.

Severity:  medium

Verify Permissions on group File   [ref]rule

To properly set the permissions of /etc/passwd, run the command:

$ sudo chmod 0644 /etc/passwd

Rationale:

The /etc/group file contains information regarding groups that are configured on the system. Protection of this file is important for system security.

Severity:  medium

Verify Permissions on gshadow File   [ref]rule

To properly set the permissions of /etc/gshadow, run the command:

$ sudo chmod 0000 /etc/gshadow

Rationale:

The /etc/gshadow file contains group password hashes. Protection of this file is critical for system security.

Severity:  medium

Verify Permissions on passwd File   [ref]rule

To properly set the permissions of /etc/passwd, run the command:

$ sudo chmod 0644 /etc/passwd

Rationale:

If the /etc/passwd file is writable by a group-owner or the world the risk of its compromise is increased. The file contains the list of accounts on the system and associated information, and protection of this file is critical for system security.

Severity:  medium

Verify Permissions on shadow File   [ref]rule

To properly set the permissions of /etc/shadow, run the command:

$ sudo chmod 0000 /etc/shadow

Rationale:

The /etc/shadow file contains the list of local system accounts and stores password hashes. Protection of this file is critical for system security. Failure to give ownership of this file to root provides the designated owner with access to sensitive information which could weaken the system security posture.

Severity:  medium

Verify that All World-Writable Directories Have Sticky Bits Set   [ref]rule

When the so-called 'sticky bit' is set on a directory, only the owner of a given file may remove that file from the directory. Without the sticky bit, any user with write access to a directory may remove any file in the directory. Setting the sticky bit prevents users from removing each other's files. In cases where there is no reason for a directory to be world-writable, a better solution is to remove that permission rather than to set the sticky bit. However, if a directory is used by a particular application, consult that application's documentation instead of blindly changing modes.
To set the sticky bit on a world-writable directory DIR, run the following command:

$ sudo chmod +t DIR

Rationale:

Failing to set the sticky bit on public directories allows unauthorized users to delete files in the directory structure.

The only authorized public directories are those temporary directories supplied with the system, or those designed to be temporary file repositories. The setting is normally reserved for directories used by the system, by users for temporary file storage (such as /tmp), and for directories requiring global read/write access.

Severity:  medium

Ensure No World-Writable Files Exist   [ref]rule

It is generally a good idea to remove global (other) write access to a file when it is discovered. However, check with documentation for specific applications before making changes. Also, monitor for recurring world-writable files, as these may be symptoms of a misconfigured application or user account. Finally, this applies to real files and not virtual files that are a part of pseudo file systems such as sysfs or procfs.

Rationale:

Data in world-writable files can be modified by any user on the system. In almost all circumstances, files can be configured using a combination of user and group permissions to support whatever legitimate access is needed without the risk caused by world-writable files.

Severity:  medium

Restrict Partition Mount Options   [ref]group

System partitions can be mounted with certain options that limit what files on those partitions can do. These options are set in the /etc/fstab configuration file, and can be used to make certain types of malicious behavior more difficult.

contains 10 rules

Add nosuid Option to /boot   [ref]rule

The nosuid mount option can be used to prevent execution of setuid programs in /boot. The SUID and SGID permissions should not be required on the boot partition. Add the nosuid option to the list of Options in the systemd.mount unit that controls mounting of /boot.

Rationale:

The presence of SUID and SGID executables should be tightly controlled. Users should not be able to execute SUID or SGID binaries from boot partitions.

Severity:  medium

Add nosuid Option to /home   [ref]rule

The nosuid mount option can be used to prevent execution of setuid programs in /home. The SUID and SGID permissions should not be required in these user data directories. Add the nosuid option to the list of Options in the systemd.mount unit that controls mounting of /home.

Rationale:

The presence of SUID and SGID executables should be tightly controlled. Users should not be able to execute SUID or SGID binaries from user home directory partitions.

Severity:  medium

Add nodev Option to Non-Root Local Partitions   [ref]rule

The nodev mount option prevents files from being interpreted as character or block devices. Legitimate character and block devices should exist only in the /dev directory on the root partition or within chroot jails built for system services. Add the nodev option to the list of Options in the systemd.mount unit that controls mounting of any non-root local partitions.

Rationale:

The nodev mount option prevents files from being interpreted as character or block devices. The only legitimate location for device files is the /dev directory located on the root partition. The only exception to this is chroot jails, for which it is not advised to set nodev on these filesystems.

Severity:  medium

Add noexec Option to /tmp   [ref]rule

The noexec mount option can be used to prevent binaries from being executed out of /tmp. Add the noexec option to the list of Options in the systemd.mount unit that controls mounting of /tmp.

Rationale:

Allowing users to execute binaries from world-writable directories such as /tmp should never be necessary in normal operation and can expose the system to potential compromise.

Severity:  medium

Add nosuid Option to /tmp   [ref]rule

The nosuid mount option can be used to prevent execution of setuid programs in /tmp. The SUID and SGID permissions should not be required in these world-writable directories. Add the nosuid option to the list of Options in the systemd.mount unit that controls mounting of /tmp.

Rationale:

The presence of SUID and SGID executables should be tightly controlled. Users should not be able to execute SUID or SGID binaries from temporary storage partitions.

Severity:  medium

Add noexec Option to /var/log   [ref]rule

The noexec mount option can be used to prevent binaries from being executed out of /var/log. Add the noexec option to the list of Options in the systemd.mount unit that controls mounting of /var/log.

Rationale:

Allowing users to execute binaries from directories containing log files such as /var/log should never be necessary in normal operation and can expose the system to potential compromise.

Severity:  medium

Add nosuid Option to /var/log   [ref]rule

The nosuid mount option can be used to prevent execution of setuid programs in /var/log. The SUID and SGID permissions should not be required in directories containing log files. Add the nosuid option to the list of Options in the systemd.mount unit that controls mounting of /var/log.

Rationale:

The presence of SUID and SGID executables should be tightly controlled. Users should not be able to execute SUID or SGID binaries from partitions designated for log files.

Severity:  medium

Add nosuid Option to /var   [ref]rule

The nosuid mount option can be used to prevent execution of setuid programs in /var. The SUID and SGID permissions should not be required for this directory. Add the nosuid option to the list of Options in the systemd.mount unit that controls mounting of /var.

Rationale:

The presence of SUID and SGID executables should be tightly controlled.

Severity:  medium

References:  BP28(R12)

Add noexec Option to /var/tmp   [ref]rule

The noexec mount option can be used to prevent binaries from being executed out of /var/tmp. Add the noexec option to the list of Options in the systemd.mount unit that controls mounting of /var/tmp.

Rationale:

Allowing users to execute binaries from world-writable directories such as /var/tmp should never be necessary in normal operation and can expose the system to potential compromise.

Severity:  medium

Identifiers:  CCE-82866-5

References:  BP28(R12), CCI-001764, SRG-OS-000368-GPOS-00154

Add nosuid Option to /var/tmp   [ref]rule

The nosuid mount option can be used to prevent execution of setuid programs in /var/tmp. The SUID and SGID permissions should not be required in these world-writable directories. Add the nosuid option to the list of Options in the systemd.mount unit that controls mounting of /var/tmp.

Rationale:

The presence of SUID and SGID executables should be tightly controlled. Users should not be able to execute SUID or SGID binaries from temporary storage partitions.

Severity:  medium

Identifiers:  CCE-82736-0

References:  BP28(R12), CCI-001764, SRG-OS-000368-GPOS-00154

Restrict Programs from Dangerous Execution Patterns   [ref]group

The recommendations in this section are designed to ensure that the system's features to protect against potentially dangerous program execution are activated. These protections are applied at the system initialization or kernel level, and defend against certain types of badly-configured or compromised programs.

contains 9 rules

Disable Core Dumps   [ref]group

A core dump file is the memory image of an executable program when it was terminated by the operating system due to errant behavior. In most cases, only software developers legitimately need to access these files. The core dump files may also contain sensitive information, or unnecessarily occupy large amounts of disk space.

Once a hard limit is set in /etc/security/limits.conf, or to a file within the /etc/security/limits.d/ directory, a user cannot increase that limit within his or her own session. If access to core dumps is required, consider restricting them to only certain users or groups. See the limits.conf man page for more information.

The core dumps of setuid programs are further protected. The sysctl variable fs.suid_dumpable controls whether the kernel allows core dumps from these programs at all. The default value of 0 is recommended.

contains 1 rule

Disable Core Dumps for SUID programs   [ref]rule

To set the runtime status of the fs.suid_dumpable kernel parameter, run the following command:

$ sudo sysctl -w fs.suid_dumpable=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
fs.suid_dumpable = 0

Rationale:

The core dump of a setuid program is more likely to contain sensitive data, as the program itself runs with greater privileges than the user who initiated execution of the program. Disabling the ability for any setuid program to write a core file decreases the risk of unauthorized access of such data.

Severity:  medium

Enable ExecShield   [ref]group

ExecShield describes kernel features that provide protection against exploitation of memory corruption errors such as buffer overflows. These features include random placement of the stack and other memory regions, prevention of execution in memory that should only hold data, and special handling of text buffers. These protections are enabled by default on 32-bit systems and controlled through sysctl variables kernel.exec-shield and kernel.randomize_va_space. On the latest 64-bit systems, kernel.exec-shield cannot be enabled or disabled with sysctl.

contains 2 rules

Restrict Exposed Kernel Pointer Addresses Access   [ref]rule

To set the runtime status of the kernel.kptr_restrict kernel parameter, run the following command:

$ sudo sysctl -w kernel.kptr_restrict=2
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
kernel.kptr_restrict = 2

Rationale:

Exposing kernel pointers (through procfs or seq_printf()) exposes kernel writeable structures which may contain functions pointers. If a write vulnerability occurs in the kernel, allowing write access to any of this structure, the kernel can be compromised. This option disallow any program without the CAP_SYSLOG capability to get the addresses of kernel pointers by replacing them with 0.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,kernel.kptr_restrict%3D1%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_kernel_kptr_restrict.conf
        overwrite: true

Enable Randomized Layout of Virtual Address Space   [ref]rule

To set the runtime status of the kernel.randomize_va_space kernel parameter, run the following command:

$ sudo sysctl -w kernel.randomize_va_space=2
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
kernel.randomize_va_space = 2

Rationale:

Address space layout randomization (ASLR) makes it more difficult for an attacker to predict the location of attack code they have introduced into a process's address space during an attempt at exploitation. Additionally, ASLR makes it more difficult for an attacker to know the location of existing code in order to re-purpose it using return oriented programming (ROP) techniques.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,kernel.randomize_va_space%3D2%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_kernel_randomize_va_space.conf
        overwrite: true

Restrict Access to Kernel Message Buffer   [ref]rule

To set the runtime status of the kernel.dmesg_restrict kernel parameter, run the following command:

$ sudo sysctl -w kernel.dmesg_restrict=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
kernel.dmesg_restrict = 1

Rationale:

Unprivileged access to the kernel syslog can expose sensitive kernel address information.

Severity:  low

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,kernel.dmesg_restrict%3D1%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_kernel_dmesg_restrict.conf
        overwrite: true

Kernel panic on oops   [ref]rule

To set the runtime status of the kernel.panic_on_oops kernel parameter, run the following command:

$ sudo sysctl -w kernel.panic_on_oops=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
kernel.panic_on_oops = 1

Warning:  The system may start to panic when it normally wouldn't. A non-catastrophic error that would have allowed the system to continue operating will now result in a panic.
Rationale:

An attacker trying to exploit the kernel may trigger kernel OOPSes, panicking the system will impede them from continuing.

Severity:  medium

References:  BP28(R9)

Disallow kernel profiling by unprivileged users   [ref]rule

To set the runtime status of the kernel.perf_event_paranoid kernel parameter, run the following command:

$ sudo sysctl -w kernel.perf_event_paranoid=2
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
kernel.perf_event_paranoid = 2

Rationale:

Kernel profiling can reveal sensitive information about kernel behaviour.

Severity:  low

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,kernel.perf_event_paranoid%3D2%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_kernel_perf_event_paranoid.conf
        overwrite: true

Disable Access to Network bpf() Syscall From Unprivileged Processes   [ref]rule

To set the runtime status of the kernel.unprivileged_bpf_disabled kernel parameter, run the following command:

$ sudo sysctl -w kernel.unprivileged_bpf_disabled=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
kernel.unprivileged_bpf_disabled = 1

Rationale:

Loading and accessing the packet filters programs and maps using the bpf() syscall has the potential of revealing sensitive information about the kernel state.

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,kernel.unprivileged_bpf_disabled%3D1%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_kernel_unprivileged_bpf_disabled.conf
        overwrite: true

Restrict usage of ptrace to descendant processes   [ref]rule

To set the runtime status of the kernel.yama.ptrace_scope kernel parameter, run the following command:

$ sudo sysctl -w kernel.yama.ptrace_scope=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
kernel.yama.ptrace_scope = 1

Rationale:

Unrestricted usage of ptrace allows compromised binaries to run ptrace on another processes of the user. Like this, the attacker can steal sensitive information from the target processes (e.g. SSH sessions, web browser, ...) without any additional assistance from the user (i.e. without resorting to phishing).

Severity:  medium

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,kernel.yama.ptrace_scope%3D1%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_kernel_yama_ptrace_scope.conf
        overwrite: true

Harden the operation of the BPF just-in-time compiler   [ref]rule

To set the runtime status of the net.core.bpf_jit_harden kernel parameter, run the following command:

$ sudo sysctl -w net.core.bpf_jit_harden=2
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:
net.core.bpf_jit_harden = 2

Rationale:

When hardened, the extended Berkeley Packet Filter just-in-time compiler will randomize any kernel addresses in the BPF programs and maps, and will not expose the JIT addresses in /proc/kallsyms.

Severity:  medium

Identifiers:  CCE-82505-9

References:  BP28(R12), CCI-000366, CM-6, SC-7(10), FMT_SMF_EXT.1, SRG-OS-000480-GPOS-00227

Remediation script:   (show)

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,net.core.bpf_jit_harden%3D2%0A
        mode: 0644
        path: /etc/sysctl.d/75-sysctl_net_core_bpf_jit_harden.conf
        overwrite: true

SELinux   [ref]group

SELinux is a feature of the Linux kernel which can be used to guard against misconfigured or compromised programs. SELinux enforces the idea that programs should be limited in what files they can access and what actions they can take.

The default SELinux policy, as configured on Red Hat Enterprise Linux CoreOS 4, has been sufficiently developed and debugged that it should be usable on almost any system with minimal configuration and a small amount of system administrator training. This policy prevents system services - including most of the common network-visible services such as mail servers, FTP servers, and DNS servers - from accessing files which those services have no valid reason to access. This action alone prevents a huge amount of possible damage from network attacks against services, from trojaned software, and so forth.

This guide recommends that SELinux be enabled using the default (targeted) policy on every Red Hat Enterprise Linux CoreOS 4 system, unless that system has unusual requirements which make a stronger policy appropriate.

contains 4 rules

Uninstall setroubleshoot-plugins Package   [ref]rule

The SETroubleshoot plugins are used to analyze SELinux AVC data. The service provides information around configuration errors, unauthorized intrusions, and other potential errors. The setroubleshoot-plugins package can be removed with the following command:

Rationale:

The SETroubleshoot service is an unnecessary daemon to have running on a server.

Severity:  low

Identifiers:  CCE-84091-8

References:  BP28(R68)

Uninstall setroubleshoot-server Package   [ref]rule

The SETroubleshoot service notifies desktop users of SELinux denials. The service provides information around configuration errors, unauthorized intrusions, and other potential errors. The setroubleshoot-server package can be removed with the following command:

Rationale:

The SETroubleshoot service is an unnecessary daemon to have running on a server.

Severity:  low

Identifiers:  CCE-84093-4

References:  BP28(R68)

Configure SELinux Policy   [ref]rule

The SELinux targeted policy is appropriate for general-purpose desktops and servers, as well as systems in many other roles. To configure the system to use this policy, add or correct the following line in /etc/selinux/config:

SELINUXTYPE=targeted
Other policies, such as mls, provide additional security labeling and greater confinement but are not compatible with many general-purpose use cases.

Rationale:

Setting the SELinux policy to targeted or a more specialized policy ensures the system will confine processes that are likely to be targeted for exploitation, such as network or system services.

Note: During the development or debugging of SELinux modules, it is common to temporarily place non-production systems in permissive mode. In such temporary cases, SELinux policies should be developed, and once work is completed, the system should be reconfigured to targeted.

Severity:  medium

Identifiers:  CCE-82532-3

References:  BP28(R66), 1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9, APO01.06, APO11.04, APO13.01, BAI03.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, MEA02.01, 3.1.2, 3.7.2, CCI-002165, CCI-002696, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.2.3.4, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.2, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-004-6 R3.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5, AC-3, AC-3(3)(a), AU-9, SC-7(21), DE.AE-1, ID.AM-3, PR.AC-4, PR.AC-5, PR.AC-6, PR.DS-5, PR.PT-1, PR.PT-3, PR.PT-4, SRG-OS-000445-GPOS-00199, SRG-APP-000233-CTR-000585

Ensure SELinux State is Enforcing   [ref]rule

The SELinux state should be set to enforcing at system boot time. In the file /etc/selinux/config, add or correct the following line to configure the system to boot into enforcing mode:

SELINUX=enforcing

Rationale:

Setting the SELinux state to enforcing ensures SELinux is able to confine potentially compromised processes to the security policy, which is designed to prevent them from causing damage to the system or further elevating their privileges.

Severity:  high

Identifiers:  CCE-82531-5

References:  BP28(R4), BP28(R66), 1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9, APO01.06, APO11.04, APO13.01, BAI03.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, MEA02.01, 3.1.2, 3.7.2, CCI-001084, CCI-002165, CCI-002696, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.2.3.4, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.2, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-004-6 R3.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5, AC-3, AC-3(3)(a), AU-9, SC-7(21), DE.AE-1, ID.AM-3, PR.AC-4, PR.AC-5, PR.AC-6, PR.DS-5, PR.PT-1, PR.PT-3, PR.PT-4, SRG-OS-000445-GPOS-00199, SRG-OS-000134-GPOS-00068

Services   [ref]group

The best protection against vulnerable software is running less software. This section describes how to review the software which Red Hat Enterprise Linux CoreOS 4 installs on a system and disable software which is not needed. It then enumerates the software packages installed on a default Red Hat Enterprise Linux CoreOS 4 system and provides guidance about which ones can be safely disabled.

Red Hat Enterprise Linux CoreOS 4 provides a convenient minimal install option that essentially installs the bare necessities for a functional system. When building Red Hat Enterprise Linux CoreOS 4 systems, it is highly recommended to select the minimal packages and then build up the system from there.

contains 9 rules

Mail Server Software   [ref]group

Mail servers are used to send and receive email over the network. Mail is a very common service, and Mail Transfer Agents (MTAs) are obvious targets of network attack. Ensure that systems are not running MTAs unnecessarily, and configure needed MTAs as defensively as possible.

Very few systems at any site should be configured to directly receive email over the network. Users should instead use mail client programs to retrieve email from a central server that supports protocols such as IMAP or POP3. However, it is normal for most systems to be independently capable of sending email, for instance so that cron jobs can report output to an administrator. Most MTAs, including Postfix, support a submission-only mode in which mail can be sent from the local system to a central site MTA (or directly delivered to a local account), but the system still cannot receive mail directly over a network.

The alternatives program in Red Hat Enterprise Linux CoreOS 4 permits selection of other mail server software (such as Sendmail), but Postfix is the default and is preferred. Postfix was coded with security in mind and can also be more effectively contained by SELinux as its modular design has resulted in separate processes performing specific actions. More information is available on its website, http://www.postfix.org.

contains 2 rules

Configure SMTP For Mail Clients   [ref]group

This section discusses settings for Postfix in a submission-only e-mail configuration.

contains 1 rule

Configure System to Forward All Mail For The Root Account   [ref]rule

Make sure that mails delivered to root user are forwarded to a monitored email address. Make sure that the address system.administrator@mail.mil is a valid email address reachable from the system in question. Use the following command to configure the alias:

$ sudo echo "root: system.administrator@mail.mil" >> /etc/aliases
$ sudo newaliases

Rationale:

A number of system services utilize email messages sent to the root user to notify system administrators of active or impending issues. These messages must be forwarded to at least one monitored email address.

Severity:  medium

Uninstall Sendmail Package   [ref]rule

Sendmail is not the default mail transfer agent and is not installed by default. The sendmail package can be removed with the following command:

Rationale:

The sendmail software was not developed with security in mind and its design prevents it from being effectively contained by SELinux. Postfix should be used instead.

Severity:  medium

Network Time Protocol   [ref]group

The Network Time Protocol is used to manage the system clock over a network. Computer clocks are not very accurate, so time will drift unpredictably on unmanaged systems. Central time protocols can be used both to ensure that time is consistent among a network of systems, and that their time is consistent with the outside world.

If every system on a network reliably reports the same time, then it is much easier to correlate log messages in case of an attack. In addition, a number of cryptographic protocols (such as Kerberos) use timestamps to prevent certain types of attacks. If your network does not have synchronized time, these protocols may be unreliable or even unusable.

Depending on the specifics of the network, global time accuracy may be just as important as local synchronization, or not very important at all. If your network is connected to the Internet, using a public timeserver (or one provided by your enterprise) provides globally accurate timestamps which may be essential in investigating or responding to an attack which originated outside of your network.

A typical network setup involves a small number of internal systems operating as NTP servers, and the remainder obtaining time information from those internal servers.

There is a choice between the daemons ntpd and chronyd, which are available from the repositories in the ntp and chrony packages respectively.

The default chronyd daemon can work well when external time references are only intermittently accesible, can perform well even when the network is congested for longer periods of time, can usually synchronize the clock faster and with better time accuracy, and quickly adapts to sudden changes in the rate of the clock, for example, due to changes in the temperature of the crystal oscillator. Chronyd should be considered for all systems which are frequently suspended or otherwise intermittently disconnected and reconnected to a network. Mobile and virtual systems for example.

The ntpd NTP daemon fully supports NTP protocol version 4 (RFC 5905), including broadcast, multicast, manycast clients and servers, and the orphan mode. It also supports extra authentication schemes based on public-key cryptography (RFC 5906). The NTP daemon (ntpd) should be considered for systems which are normally kept permanently on. Systems which are required to use broadcast or multicast IP, or to perform authentication of packets with the Autokey protocol, should consider using ntpd.

Refer to https://docs.fedoraproject.org/en-US/fedora/latest/system-administrators-guide/servers/Configuring_NTP_Using_the_chrony_Suite/ for more detailed comparison of features of chronyd and ntpd daemon features respectively, and for further guidance how to choose between the two NTP daemons.

The upstream manual pages at https://chrony-project.org/documentation.html for chronyd and http://www.ntp.org for ntpd provide additional information on the capabilities and configuration of each of the NTP daemons.

contains 3 rules

The Chrony package is installed   [ref]rule

System time should be synchronized between all systems in an environment. This is typically done by establishing an authoritative time server or set of servers and having all systems synchronize their clocks to them. The chrony package can be installed with the following command:

Rationale:

Time synchronization is important to support time sensitive security mechanisms like Kerberos and also ensures log files have consistent time records across the enterprise, which aids in forensic investigations.

Severity:  medium

Enable the NTP Daemon   [ref]rule

As a user with administrator privileges, log into a node in the relevant pool:

$ oc debug node/$NODE_NAME
At the
sh-4.4#
prompt, run:
# chroot /host
Run the following command to determine the current status of the chronyd service:
$ sudo systemctl is-active chronyd
If the service is running, it should return the following:
active
Note: The chronyd daemon is enabled by default.

As a user with administrator privileges, log into a node in the relevant pool:
$ oc debug node/$NODE_NAME
At the
sh-4.4#
prompt, run:
# chroot /host
Run the following command to determine the current status of the ntpd service:
$ sudo systemctl is-active ntpd
If the service is running, it should return the following:
active
Note: The ntpd daemon is not enabled by default. Though as mentioned in the previous sections in certain environments the ntpd daemon might be preferred to be used rather than the chronyd one. Refer to: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/system_administrators_guide/ch-configuring_ntp_using_the_chrony_suite for guidance which NTP daemon to choose depending on the environment used.

Rationale:

Enabling some of chronyd or ntpd services ensures that the NTP daemon will be running and that the system will synchronize its time to any servers specified. This is important whether the system is configured to be a client (and synchronize only its own clock) or it is also acting as an NTP server to other systems. Synchronizing time is essential for authentication services such as Kerberos, but it is also important for maintaining accurate logs and auditing possible security breaches.

The chronyd and ntpd NTP daemons offer all of the functionality of ntpdate, which is now deprecated.

Severity:  medium

A remote time server for Chrony is configured   [ref]rule

Chrony is a daemon which implements the Network Time Protocol (NTP). It is designed to synchronize system clocks across a variety of systems and use a source that is highly accurate. More information on chrony can be found at http://chrony.tuxfamily.org/. Chrony can be configured to be a client and/or a server. Add or edit server or pool lines to /etc/chrony.conf as appropriate:

server <remote-server>
Multiple servers may be configured.

Rationale:

If chrony is in use on the system proper configuration is vital to ensuring time synchronization is working properly.

Severity:  medium

SSH Server   [ref]group

The SSH protocol is recommended for remote login and remote file transfer. SSH provides confidentiality and integrity for data exchanged between two systems, as well as server authentication, through the use of public key cryptography. The implementation included with the system is called OpenSSH, and more detailed documentation is available from its website, https://www.openssh.com. Its server program is called sshd and provided by the RPM package openssh-server.

contains 4 rules

Configure OpenSSH Server if Necessary   [ref]group

If the system needs to act as an SSH server, then certain changes should be made to the OpenSSH daemon configuration file /etc/ssh/sshd_config. The following recommendations can be applied to this file. See the sshd_config(5) man page for more detailed information.

contains 3 rules

Set SSH Client Alive Count Max   [ref]rule

The SSH server sends at most ClientAliveCountMax messages during a SSH session and waits for a response from the SSH client. The option ClientAliveInterval configures timeout after each ClientAliveCountMax message. If the SSH server does not receive a response from the client, then the connection is considered unresponsive and terminated. For SSH earlier than v8.2, a ClientAliveCountMax value of 0 causes a timeout precisely when the ClientAliveInterval is set. Starting with v8.2, a value of 0 disables the timeout functionality completely. If the option is set to a number greater than 0, then the session will be disconnected after ClientAliveInterval * ClientAliveCountMax seconds without receiving a keep alive message.

Rationale:

This ensures a user login will be terminated as soon as the ClientAliveInterval is reached.

Severity:  medium

Remediation script:   (show)

Complexity:low
Disruption:low
Reboot:false
Strategy:restrict
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,{{ 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}}
        mode: 0600
        path: /etc/ssh/sshd_config
        overwrite: true

Set SSH Client Alive Interval   [ref]rule

SSH allows administrators to set a network responsiveness timeout interval. After this interval has passed, the unresponsive client will be automatically logged out.

To set this timeout interval, edit the following line in /etc/ssh/sshd_config as follows:

ClientAliveInterval 600


The timeout interval is given in seconds. For example, have a timeout of 10 minutes, set interval to 600.

If a shorter timeout has already been set for the login shell, that value will preempt any SSH setting made in /etc/ssh/sshd_config. Keep in mind that some processes may stop SSH from correctly detecting that the user is idle.

Warning:  SSH disconnecting unresponsive clients will not have desired effect without also configuring ClientAliveCountMax in the SSH service configuration.
Warning:  Following conditions may prevent the SSH session to time out:
  • Remote processes on the remote machine generates output. As the output has to be transferred over the network to the client, the timeout is reset every time such transfer happens.
  • Any scp or sftp activity by the same user to the host resets the timeout.
Rationale:

Terminating an idle ssh session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been let unattended.

Severity:  medium

Remediation script:   (show)

Complexity:low
Disruption:low
Reboot:false
Strategy:restrict
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,{{ 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}}
        mode: 0600
        path: /etc/ssh/sshd_config
        overwrite: true

Verify Permissions on SSH Server Private *_key Key Files   [ref]rule

SSH server private keys - files that match the /etc/ssh/*_key glob, have to have restricted permissions. If those files are owned by the root user and the root group, they have to have the 0640 permission or stricter. If they are owned by the root user, but by a dedicated group ssh_keys, they can have the 0640 permission or stricter.

Rationale:

If an unauthorized user obtains the private SSH host key file, the host could be impersonated.

Severity:  medium

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