RHEL 9 must disable the ability of a user to accidentally press Ctrl-Alt-Del and cause a system to shut down or reboot.

STIG ID: RHEL-09-271105  |  SRG: SRG-OS-000480-GPOS-00227 | Severity: medium |  CCI: CCI-000366

Vulnerability Discussion

A locally logged-in user who presses Ctrl-Alt-Del, when at the console, can reboot the system. If accidentally pressed, as could happen in the case of mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot.

Check

Verify RHEL 9 is configured to ignore the Ctrl-Alt-Del sequence in the GNOME desktop with the following command:

Note: This requirement assumes the use of the RHEL 9 default graphical user interface, the GNOME desktop environment. If the system does not have any graphical user interface installed, this requirement is Not Applicable.

$ gsettings get org.gnome.settings-daemon.plugins.media-keys logout

"['']"

If the GNOME desktop is configured to shut down when Ctrl-Alt-Del is pressed, this is a finding.

Fix

Configure RHEL 9 to ignore the Ctrl-Alt-Del sequence in the GNOME desktop.

Add or update the [org/gnome/settings-daemon/plugins/media-keys] section of the /etc/dconf/db/local.d/00-security-settings database file and add or update the following lines:

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

Run the following command to update the database:

$ sudo dconf update
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