Ensure no users have .forward files

LowLevel 2Manual reviewcos

Description

The .forward file specifies an email address to forward the user's mail to. Use of the .forward file poses a security risk in that sensitive data may be inadvertently transferred outside the organization. The .forward file also poses a risk as it can be used to execute commands that may perform unintended actions.

How it is checked

Audit method: Manual review

This recommendation cannot be checked automatically. A scan lists it with these instructions when you pass --include-manual.

Run the following script and verify no results are returned: #!/bin/bash grep -E -v '^(root|system-halt|sync|system-shutdown)' /etc/passwd | awk -F: '($7 != "'"$(which nologin)"'" && $7 != "/bin/false") { print $1 " " $6 }' | while read user dir; do if [ ! -d "$dir" ]; then echo "The home directory ($dir) of user $user does not exist." else if [ ! -h "$dir/.forward" -a -f "$dir/.forward" ]; then echo ".forward file $dir/.forward exists" fi fi done

How it is fixed

Fix method: Guidance or infrastructure patch

Making global modifications to users' files without alerting the user community can result in unexpected outages and unhappy users. Therefore, it is recommended that a monitoring policy be established to report user .forward files and determine the action to be taken in accordance with site policy.

Properties

Operating systems: Any
Tags: container-optimized-oscos
Reference: CIS Google Container-Optimized OS Benchmark v1.2.0 - 6.2.11 Ensure no users have .forward files