CIS Ubuntu 14.04 LTS - 6.2.11 Ensure no users have .forward files

6.2.11 Ensure no users have .forward files (Scored)

Profile Applicability

• Level 1 - Server
• Level 1 - Workstation

Description

The .forward file specifies an email address to forward the user's mail to.

Rationale

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.

Audit Procedure

Run the following script and verify no results are returned:

#!/bin/bash

cat /etc/passwd | egrep -v '^(root|halt|sync|shutdown)' | awk -F: '($7 != "/sbin/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

Expected Result

No output should be returned.

Remediation

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.

Default Value

Not applicable.

References

None

CIS Controls

7 Email and Web Browser Protections - Email and Web Browser Protections

Profile

• Level 1