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The RHEL 8 SSH daemon must not allow authentication using known host’s authentication.
Configuring this setting for the SSH daemon provides additional assurance that remote logon via SSH will require a password, even in the event of misconfiguration elsewhere.
Red Hat Enterprise Linux 8 Security Technical Implementation Guide
Check Text ( C-32959r567616_chk )
Verify the SSH daemon does not allow authentication using known host’s authentication with the following command:
$ sudo grep -i IgnoreUserKnownHosts /etc/ssh/sshd_config
If the value is returned as "no", the returned line is commented out, or no output is returned, this is a finding.
Fix Text (F-32934r567617_fix)
Configure the SSH daemon to not allow authentication using known host’s authentication.
Add the following line in "/etc/ssh/sshd_config", or uncomment the line and set the value to "yes":
The SSH daemon must be restarted for the changes to take effect. To restart the SSH daemon, run the following command:
$ sudo systemctl restart sshd.service