RHEL 9 SSH server configuration file must have mode 0600 or less permissive.

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 should be owned by the correct group to prevent unauthorized changes.

Check

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

$ sudo find /etc/ssh/sshd_config /etc/ssh/sshd_config.d -exec stat -c "%a %n" {} \;

600 /etc/ssh/sshd_config
700 /etc/ssh/sshd_config.d
600 /etc/ssh/sshd_config.d/50-cloud-init.conf
600 /etc/ssh/sshd_config.d/50-redhat.conf

If the "/etc/ssh/sshd_config" permissions are not "0600", this is a finding.

Fix

Configure the "/etc/ssh/sshd_config" permissions to be "0600" with the following command:

$ sudo chmod 0600 /etc/ssh/sshd_config