The Ubuntu operating system must be configured so that Advance Package Tool (APT) removes all software components after updated versions have been installed.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-238370	SRG-OS-000437-GPOS-00194	UBTU-20-010449	SV-238370r958936_rule	2025-03-03	2

Description
Previous versions of software components that are not removed from the information system after updates have been installed may be exploited by adversaries. Some information technology products may remove older versions of software automatically from the information system.

ℹ️ Check
Verify is configured to remove all software components after updated versions have been installed with the following command: $ grep -i remove-unused /etc/apt/apt.conf.d/50unattended-upgrades Unattended-Upgrade::Remove-Unused-Dependencies "true"; Unattended-Upgrade::Remove-Unused-Kernel-Packages "true"; If the "::Remove-Unused-Dependencies" and "::Remove-Unused-Kernel-Packages" parameters are not set to "true" or are missing or commented out, this is a finding.

ℹ️ Check

Verify is configured to remove all software components after updated versions have been installed with the following command: $ grep -i remove-unused /etc/apt/apt.conf.d/50unattended-upgrades Unattended-Upgrade::Remove-Unused-Dependencies "true"; Unattended-Upgrade::Remove-Unused-Kernel-Packages "true"; If the "::Remove-Unused-Dependencies" and "::Remove-Unused-Kernel-Packages" parameters are not set to "true" or are missing or commented out, this is a finding.

✔️ Fix
Configure APT to remove all software components after updated versions have been installed. Add or updated the following options to the "/etc/apt/apt.conf.d/50unattended-upgrades" file: Unattended-Upgrade::Remove-Unused-Dependencies "true"; Unattended-Upgrade::Remove-Unused-Kernel-Packages "true";