5.4.5 Ensure default user shell timeout is 900 seconds or less - /etc/profile

Information

The default TMOUT determines the shell timeout for users. The TMOUT value is measured in
seconds.

Rationale:

Having no timeout value associated with a shell could allow an unauthorized user access to
another user's shell session (e.g. user walks away from their computer and doesn't lock the
screen). Setting a timeout value at least reduces the risk of this happening.

Solution

Edit the /etc/bashrc and /etc/profile files (and the appropriate files for any other shell
supported on your system) and add or edit any umask parameters as follows:

TMOUT=900

Notes:

The audit and remediation in this recommendation apply to bash and shell. If other shells
are supported on the system, it is recommended that their configuration files also are
checked. Other methods of setting a timeout exist for other shells not covered here.

Ensure that the timeout conforms to your local policy.

See Also

https://workbench.cisecurity.org/files/2420