The Oracle Linux operating system must be configured so the SSH private host key files have mode 0640 or less permissive.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-221859	SRG-OS-000480-GPOS-00227	OL07-00-040420	SV-221859r991589_rule	2025-05-08	3

Description
If an unauthorized user obtains the private SSH host key file, the host could be impersonated.

ℹ️ Check
Verify the SSH private host key files have mode 0640 or less permissive. The following command will find all SSH private key files on the system and list their modes: # find / -name 'ssh_hostkey' \| xargs ls -lL -rw-r----- 1 root ssh_keys 112 Apr 1 11:59 ssh_host_dsa_key -rw-r----- 1 root ssh_keys 202 Apr 1 11:59 ssh_host_key -rw-r----- 1 root ssh_keys 352 Apr 1 11:59 ssh_host_rsa_key If any file has a mode more permissive than 0640, this is a finding.

ℹ️ Check

Verify the SSH private host key files have mode 0640 or less permissive. The following command will find all SSH private key files on the system and list their modes: # find / -name '*ssh_host*key' | xargs ls -lL -rw-r----- 1 root ssh_keys 112 Apr 1 11:59 ssh_host_dsa_key -rw-r----- 1 root ssh_keys 202 Apr 1 11:59 ssh_host_key -rw-r----- 1 root ssh_keys 352 Apr 1 11:59 ssh_host_rsa_key If any file has a mode more permissive than 0640, this is a finding.

✔️ Fix
Configure the mode of SSH private host key files under "/etc/ssh" to "0640" with the following command: # chmod 0640 /path/to/file/ssh_host*key