RHEL 9 SSH server configuration files' permissions must not be modified.

STIG ID: RHEL-09-255115  |  SRG: SRG-OS-000480-GPOS-00227 |  Severity: medium |  CCI: CCI-000366 |  Vulnerability Id: V-257999

Vulnerability Discussion

Service configuration files enable or disable features of their respective services, that if configured incorrectly, can lead to insecure and vulnerable configurations. Therefore, service configuration files must have correct permissions (owner, group owner, mode) to prevent unauthorized changes.

Check

Verify the permissions of the "/etc/ssh/sshd_config" file with the following command:

$ sudo rpm --verify openssh-server | awk '! ($2 == "c" && $1 ~ /^.\..\.\.\.\..\./) {print $0}'

If the command returns any output, this is a finding.

Fix

Run the following commands to restore the correct permissions of OpenSSH server configuration files:

$ rpm --setugids openssh-server
$ rpm --setperms openssh-server