Title

RHEL 9 SSH daemon must be configured to use privilege separation. (Cat II impact)

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 nonprivileged section.

Check Content

Verify the SSH daemon performs privilege separation with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*useprivilegeseparation' UsePrivilegeSeparation sandbox If the "UsePrivilegeSeparation" keyword is set to "no", the returned line is commented out, or no output is returned, this is a finding.

Fix Text

Configure the SSH daemon to perform privilege separation. Add the following line in "/etc/ssh/sshd_config", or uncomment the line and set the value to "yes" or "sandbox": UsePrivilegeSeparation sandbox The SSH service must be restarted for changes to take effect: $ sudo systemctl restart sshd.service

Additional Identifiers

Rule ID: SV-258010r952216_rule

Vulnerability ID: V-258010

Group Title: SRG-OS-000480-GPOS-00227

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.