Vulnerability Discussion
SSH environment options potentially allow users to bypass access restriction in some configurations.
Check
Verify that unattended or automatic logon via SSH is disabled 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*permituserenvironment'
PermitUserEnvironment no
If "PermitUserEnvironment" is set to "yes", is missing completely, or is commented out, this is a finding.
If the required value is not set, this is a finding.
Fix
Configure the RHEL 9 SSH daemon to not allow unattended or automatic logon to the system.
Add or edit the following line in the "/etc/ssh/sshd_config" file:
PermitUserEnvironment no
Restart the SSH daemon for the setting to take effect:
$ sudo systemctl restart sshd.service