DISA STIGS Viewer

Ubuntu 22.04 LTS must automatically exit interactive command shell user sessions after 15 minutes of inactivity.

Overview

Finding ID Version Rule ID IA Controls Severity
V-260554 UBTU-22-412030 SV-260554r958636_rule   Medium
Description
Terminating an idle interactive command shell user session within a short time period reduces the window of opportunity for unauthorized personnel to take control of it when left unattended in a virtual terminal or physical console.
STIG Date
Canonical Ubuntu 22.04 LTS Security Technical Implementation Guide 2025-05-16

Details

Check Text (C-64283r953473_chk)
Verify Ubuntu 22.04 LTS is configured to automatically exit interactive command shell user sessions after 15 minutes of inactivity or less by using the following command:

$ sudo grep -E "\bTMOUT=[0-9]+" /etc/bash.bashrc /etc/profile.d/*
/etc/profile.d/99-terminal_tmout.sh:TMOUT=900

If "TMOUT" is not set to "900" or less, is set to "0", is commented out, or missing, this is a finding.
Fix Text (F-64191r953474_fix)
Configure Ubuntu 22.04 LTS to exit interactive command shell user sessions after 15 minutes of inactivity.

Create and/or append a custom file under "/etc/profile.d/" by using the following command:

$ sudo su -c "echo TMOUT=900 >> /etc/profile.d/99-terminal_tmout.sh"

This will set a timeout value of 15 minutes for all future sessions.

To set the timeout for the current sessions, execute the following command over the terminal session:

$ export TMOUT=900