The systemd Ctrl-Alt-Delete burst key sequence in RHEL 9 must be disabled.

STIG ID: RHEL-09-211045  |  SRG: SRG-OS-000324-GPOS-00125 | Severity: high |  CCI: CCI-000366,CCI-002235

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

Satisfies: SRG-OS-000324-GPOS-00125, SRG-OS-000480-GPOS-00227

Check

Verify RHEL 9 is configured to not reboot the system when Ctrl-Alt-Delete is pressed seven times within two seconds with the following command:

$ grep -i ctrl /etc/systemd/system.conf

CtrlAltDelBurstAction=none

If the "CtrlAltDelBurstAction" is not set to "none", commented out, or is missing, this is a finding.

Fix

Configure the system to disable the CtrlAltDelBurstAction by added or modifying the following line in the "/etc/systemd/system.conf" configuration file:

CtrlAltDelBurstAction=none

Reload the daemon for this change to take effect.

$ sudo systemctl daemon-reload
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