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

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-219156	UBTU-18-010017	SV-219156r610963_rule		Medium

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.

STIG	Date
Canonical Ubuntu 18.04 LTS Security Technical Implementation Guide	2020-12-09

Details

Check Text ( C-20881r304796_chk )
Verify Advance package Tool (APT) is configured to remove all software components after updated versions have been installed. Check that APT is configured to remove all software components after updating 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 are commented out, this is a finding.

Check Text ( C-20881r304796_chk )

Verify Advance package Tool (APT) is configured to remove all software components after updated versions have been installed.

Check that APT is configured to remove all software components after updating 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 are commented out, this is a finding.

Fix Text (F-20880r304797_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";