SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts.
Check
Verify the SSH daemon does not allow rhosts authentication with the following command:
$ sshd -T | grep ignorerhosts
ignorerhosts yes
If the "IgnoreRhosts" keyword is set to "no", this is a finding.
Fix
Configure the SSH daemon to not allow rhosts authentication.
Add the following line to "/etc/ssh/sshd_config", or uncomment the line and set the value to "yes":
IgnoreRhosts yes
Alternatively, add the setting to an include file if the line "Include /etc/ssh/sshd_config.d/*.conf" is found at the top of the "/etc/ssh/sshd_config" file: