RHEL-09-255145 RHEL 9 SSH daemon must not allow rhosts authentication.
All changes in this version
Maps to CM-6 via CCI-000366
Title
RHEL 9 SSH daemon must not allow rhosts authentication.
Control
Verify the SSH daemon does not allow rhosts authentication 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*ignorerhosts' IgnoreRhosts yes If the value is returned as "no", the returned line is commented out, or no output is returned, this is a finding.
Discussion
SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts.
Related controls
CCI-000366
Fix
Configure the SSH daemon to not allow rhosts authentication. Add the following line to "/etc/ssh/sshd_config" or to a file in "/etc/ssh/sshd_config.d", or uncomment the line and set the value to "yes": IgnoreRhosts yes The SSH service must be restarted for changes to take effect: $ sudo systemctl restart sshd.service