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The Ubuntu operating system must disable the x86 Ctrl-Alt-Delete key sequence.


Finding ID Version Rule ID IA Controls Severity
V-238380 UBTU-20-010460 SV-238380r832974_rule High
A locally logged-on user who presses Ctrl-Alt-Delete, when at the console, can reboot the system. If accidentally pressed, as could happen in the case of a mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot.
Canonical Ubuntu 20.04 LTS Security Technical Implementation Guide 2022-09-07


Check Text ( C-41590r832972_chk )
Verify the Ubuntu operating system is not configured to reboot the system when Ctrl-Alt-Delete is pressed.

Check that the "ctrl-alt-del.target" (otherwise also known as reboot.target) is not active with the following command:

$ sudo systemctl status ctrl-alt-del.target
Loaded: masked (Reason: Unit ctrl-alt-del.target is masked.)
Active: inactive (dead)

If the "ctrl-alt-del.target" is not masked, this is a finding.
Fix Text (F-41549r832973_fix)
Configure the system to disable the Ctrl-Alt-Delete sequence for the command line with the following commands:

$ sudo systemctl disable ctrl-alt-del.target

$ sudo systemctl mask ctrl-alt-del.target

Reload the daemon to take effect:

$ sudo systemctl daemon-reload