RHEL 9 CIS

Configure a RHEL 9 machine to be CIS compliant

Based on CIS RedHat Enterprise Linux 9 Benchmark v1.0.0 - 11-30-2022

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Community

Join us on our Discord Server to ask questions, discuss features, or just chat with other Ansible-Lockdown users.

Contributing

Issues and Pull requests are welcome please ensure that all commits are signed-off-by and gpg-signed. Refer to Contributing Guide

Caution(s)

This role will make changes to the system which may have unintended consequences. This is not an auditing tool but rather a remediation tool to be used after an audit has been conducted.

Check Mode is not supported! The role will complete in check mode without errors, but it is not supported and should be used with caution. The RHEL8-CIS-Audit role or a compliance scanner should be used for compliance checking over check mode.

This role was developed against a clean install of the Operating System. If you are implementing to an existing system please review this role for any site specific changes that are needed.

To use the release version, please point to the main branch and relevant release for the cis benchmark you wish to work with.

Matching a security Level for CIS

It is possible to only run level 1 or level 2 controls for CIS. This is managed using tags:

• level1-server
• level1-workstation
• level2-server
• level2-workstation

The control found in the defaults main also needs to reflect this, as this control is the testing that takes place if you are using the audit component.

Coming from a previous release

CIS release always contains changes, it is highly recommended to review the new references and available variables. This has changed significantly since the ansible-lockdown initial release. This is now compatible with python3 if it is found to be the default interpreter. This does come with prerequisites which configure the system accordingly.

Further details can be seen in the Changelog

Auditing (new)

This can be turned on or off within the defaults/main.yml file with the variables setup_audit and run_audit. The value is false by default. Please refer to the wiki for more details. The defaults file also populates the goss checks to check only the controls that have been enabled in the ansible role.

This is a much quicker, very lightweight, checking (where possible) config compliance and live/running settings.

A new form of auditing has been developed by using a small (12MB) go binary called goss along with the relevant configurations to check without the need for infrastructure or other tooling. This audit will not only check the config has the correct setting but aims to capture if it is running with that configuration also try to remove false positives in the process.

Refer to RHEL9-CIS-Audit.

Documentation

• Read The Docs
• Getting Started
• Customizing Roles
• Per-Host Configuration
• Getting the Most Out of the Role

Requirements

RHEL 9 Almalinux 9 Rocky 9 OracleLinux 9

• Access to download or add the goss binary and content to the system if using auditing (other options are available on how to get the content to the system.)

CentOS stream - while this will generally work it is not supported and requires the following variable setting

os_check: false

General:

• Basic knowledge of Ansible, below are some links to the Ansible documentation to help get started if you are unfamiliar with Ansible

  • Main Ansible documentation page
  • Ansible Getting Started
  • Tower User Guide
  • Ansible Community Info
• Functioning Ansible and/or Tower Installed, configured, and running. This includes all of the base Ansible/Tower configurations, needed packages installed, and infrastructure setup.
• Please read through the tasks in this role to gain an understanding of what each control is doing. Some of the tasks are disruptive and can have unintended consiquences in a live production system. Also familiarize yourself with the variables in the defaults/main.yml file.

Technical Dependencies:

• Python3
• Ansible 2.10+
• python-def (should be included in RHEL 9)
• libselinux-python
• pip packages
  • jmespath
• collections found in collections/requirements.yml

pre-commit is available if installed on your host for pull request testing.

Role Variables

This role is designed that the end user should not have to edit the tasks themselves. All customizing should be done by overriding the required varaibles as found in defaults/main.yml file. e.g. using inventory, group_vars, extra_vars

Tags

There are many tags available for added control precision. Each control has it's own set of tags noting what level, if it's scored/notscored, what OS element it relates to, if it's a patch or audit, and the rule number.

Below is an example of the tag section from a control within this role. Using this example if you set your run to skip all controls with the tag services, this task will be skipped. The opposite can also happen where you run only controls tagged with services.

      tags:
      - level1-server
      - level1-workstation
      - scored
      - avahi
      - services
      - patch
      - rule_2.2.4

Community Contribution

We encourage you (the community) to contribute to this role. Please read the rules below.

• Your work is done in your own individual branch. Make sure to Signed-off and GPG sign all commits you intend to merge.
• All community Pull Requests are pulled into the devel branch
• Pull Requests into devel will confirm your commits have a GPG signature, Signed-off, and a functional test before being approved
• Once your changes are merged and a more detailed review is complete, an authorized member will merge your changes into the main branch for a new release

Known Issues

CIS 1.2.4 - repo_gpgcheck is not carried out for RedHat hosts as the default repos do not have this function. This also affect EPEL(not covered by var).

• Rocky and Alma not affected. Variable used to unset. rhel9cis_rhel_default_repo: true # to be set to false if using repo that does have this ability

Pipeline Testing

uses:

• ansible-core 2.12
• ansible collections - pulls in the latest version based on requirements file
• Runs the audit using the devel branch
• Runs the pre-commit setup on the PR to ensure everything is in place as expected.
• This is an automated test that occurs on pull requests into devel

Local Testing

• Ansible

  • ansible-base 2.10.17 - python 3.8
  • ansible-core 2.13.4 - python 3.10
  • ansible-core 2.15.1 - python 3.11

Added Extras

• makefile - this is there purely for testing and initial setup purposes.
• pre-commit can be tested and can be run from within the directory

pre-commit run

Credits and Thanks

Based on an original concept by Sam Doran

Massive thanks to the fantastic community and all its members.

This includes a huge thanks and credit to the original authors and maintainers.

Mark Bolwell, George Nalen, Steve Williams, Fred Witty