Vulnerability Discussion

SSH daemon privilege separation causes the SSH process to drop root privileges when not needed, which would decrease the impact of software vulnerabilities in the unprivileged section.

Check

Verify the SSH daemon performs privilege separation.

Check that the SSH daemon performs privilege separation with the following command:

# grep -i usepriv /etc/ssh/sshd_config

UsePrivilegeSeparation sandbox

If the "UsePrivilegeSeparation" keyword is set to "no", is missing, or the returned line is commented out, this is a finding.

Fix

Uncomment the "UsePrivilegeSeparation" keyword in "/etc/ssh/sshd_config" (this file may be named differently or be in a different location if using a version of SSH that is provided by a third-party vendor) and set the value to "sandbox" or "yes":

UsePrivilegeSeparation sandbox

The SSH service must be restarted for changes to take effect.