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V-238370

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-238370r958936_rule

STIG

Canonical Ubuntu 20.04 LTS Security Technical Implementation Guide

Version

V2R4

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 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 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";