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V-219156

CAT II (Medium)

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

Rule ID

SV-219156r958936_rule

STIG

Canonical Ubuntu 18.04 LTS Security Technical Implementation Guide

Version

V2R15

CCIs

CCI-002617

Discussion

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.

Check Content

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

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";