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V-238379

CAT I (High)

The Ubuntu operating system must disable the x86 Ctrl-Alt-Delete key sequence if a graphical user interface is installed.

Rule ID

SV-238379r991589_rule

STIG

Canonical Ubuntu 20.04 LTS Security Technical Implementation Guide

Version

V2R4

CCIs

CCI-000366

Discussion

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 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.

Check Content

Verify the Ubuntu operating system is not configured to reboot the system when Ctrl-Alt-Delete is pressed when using a graphical user interface.

Check that the "logout" target is not bound to an action with the following command:

# grep logout /etc/dconf/db/local.d/*

logout=''

If the "logout" key is bound to an action, is commented out, or is missing, this is a finding.

Fix Text

Configure the system to disable the Ctrl-Alt-Delete sequence when using a graphical user interface by creating or editing the /etc/dconf/db/local.d/00-disable-CAD file.

Add the setting to disable the Ctrl-Alt-Delete sequence for the graphical user interface:

[org/gnome/settings-daemon/plugins/media-keys]
logout=''

Update the dconf settings:

# dconf update