5.3.5 Ensure default user shell timeout is 900 seconds or less

Information

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

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/bash/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

See Also

https://workbench.cisecurity.org/benchmarks/12218