All network connections associated with a communication session must be terminated at the end of the session or after 10 minutes of inactivity from the user at a command prompt, except to fulfill documented and validated mission requirements.

From Red Hat Enterprise Linux 7 Security Technical Implementation Guide

SV-86847r3_rule All network connections associated with a communication session must be terminated at the end of the session or after 10 minutes of inactivity from the user at a command prompt, except to fulfill documented and validated mission requirements.

Vulnerability discussion

Terminating an idle session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended. In addition, quickly terminating an idle session will also free up resources committed by the managed network element. Terminating network connections associated with communications sessions includes, for example, de-allocating associated TCP/IP address/port pairs at the operating system level and de-allocating networking assignments at the application level if multiple application sessions are using a single operating system-level network connection. This does not mean that the operating system terminates all sessions or network access; it only ends the inactive session and releases the resources associated with that session.

Check content

Verify the operating system terminates all network connections associated with a communications session at the end of the session or based on inactivity. Check the value of the system inactivity timeout with the following command: # grep -i tmout /etc/bashrc /etc/profile.d/* TMOUT=600 If "TMOUT" is not set to "600" or less in "/etc/bashrc" or in a script created to enforce session termination after inactivity, this is a finding.

Fix text

Configure the operating system to terminate all network connections associated with a communications session at the end of the session or after a period of inactivity. Add or update the following lines in "/etc/profile". TMOUT=600 readonly TMOUT export TMOUT Or create a script to enforce the inactivity timeout (for example /etc/profile.d/tmout.sh) such as: #!/bin/bash TMOUT=600 readonly TMOUT export TMOUT

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