Vulnerability Discussion

Previous versions of software components that are not removed from the information system after updates have been installed may be exploited by some adversaries.

Check

Verify RHEL 9 removes all software components after updated versions have been installed with the following command:

$ sudo grep -i clean_requirements_on_remove /etc/dnf/dnf.conf
clean_requirements_on_remove=True

If "clean_requirements_on_remove" is not set to either "1", "true", or "yes" (keywords containing letters are case insensitive), this is a finding.

Fix

Configure RHEL 9 to remove all software components after updated versions have been installed.

Edit the file "/etc/dnf/dnf.conf" by adding or editing the following line:

clean_requirements_on_remove=True

Note: Any of the following are acceptable: "1", "true", or "yes" (keywords containing letters are case insensitive).