Vulnerability Discussion

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not log out because of the temporary nature of the absence. Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity, operating systems need to be able to identify when a user's session has idled and take action to initiate the session lock.

The screen and tmux packages allow for a session lock to be implemented and configured.

Check

Verify the operating system has the screen package installed.

Check to see if the screen package is installed with the following command:

# yum list installed screen
screen-4.3.1-3-x86_64.rpm

If the screen package is not installed, check to see if the tmux package is installed with the following command:

# yum list installed tmux
tmux-1.8-4.el7.x86_64.rpm

If either the screen package or the tmux package is not installed, this is a finding.

Fix

Install the screen package to allow the initiation of a session lock after a 15-minute period of inactivity.

Install the screen program (if it is not on the system) with the following command:

# yum install screen

OR

Install the tmux program (if it is not on the system) with the following command:

# yum install tmux