The x86 Ctrl-Alt-Delete key sequence must be disabled.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-75541	UBTU-16-010630	SV-90221r3_rule		High

Description

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. In the GNOME graphical environment, risk of unintentional reboot from the Ctrl-Alt-Delete sequence is reduced because the user will be prompted before any action is taken.

STIG	Date
Canonical Ubuntu 16.04 Security Technical Implementation Guide	2020-05-29

Details

Check Text ( C-75245r2_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: # systemctl status ctrl-alt-del.target reboot.target - Reboot Loaded: loaded (/usr/lib/systemd/system/reboot.target; disabled) Active: inactive (dead) Docs: man:systemd.special(7) If the "ctrl-alt-del.target" is active, this is a finding.

Fix Text (F-82169r3_fix)
Configure the system to disable the Ctrl-Alt-Delete sequence for the command line with the following command: # sudo systemctl mask ctrl-alt-del.target And reload the daemon to take effect # sudo systemctl daemon-reload