RHEL 10 must be configured so that the Secure Shell (SSH) daemon does not allow known hosts authentication.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-281257 | RHEL-10-700540 | SV-281257r1184757_rule | CCI-002696 | medium |
| Description | ||||
| Configuring the "IgnoreUserKnownHosts" setting for the SSH daemon provides additional assurance that remote login via SSH will require a password, even in the event of misconfiguration elsewhere. OpenSSH uses the first occurrence of a keyword it sees, and drop-in files are read in lexicographical order at the start of the configuration. Red Hat recommends using drop-in files rather than changing base configuration files. | ||||
| STIG | Date | |||
| Red Hat Enterprise Linux 10 Security Technical Implementation Guide | 2026-03-11 | |||
Details
Check Text (C-281257r1184757_chk)
Verify RHEL 10 SSH daemons do not allow known hosts 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*ignoreuserknownhosts'
/etc/ssh/sshd_config.d/10-stig.conf:IgnoreUserKnownHosts yes
Verify the runtime setting with the following command:
$ sudo sshd -T | grep -i ignoreuserknownhosts
ignoreuserknownhosts yes
If the "IgnoreUserKnownHosts" keyword is not set to "yes" in a drop-in that lexicographically precedes 50-redhat.conf, or if no output is returned, this is a finding.
Fix Text (F-85723r1166722_fix)
Configure RHEL 10 SSH daemons to not allow known hosts authentication.
In "/etc/ssh/sshd_config.d", create a drop file that will lexicographically precede 50-redhat.conf and add the following line:
IgnoreUserKnownHosts yes
Restart the SSH service with the following command for the changes to take effect:
$ sudo systemctl restart sshd.service