The Oracle Linux operating system must be configured so the SSH private host key files have mode 0600 or less permissive.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-221859	OL07-00-040420	SV-221859r792803_rule		Medium

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

STIG	Date
Oracle Linux 7 Security Technical Implementation Guide	2021-12-06

Details

Check Text ( C-23574r792801_chk )
Verify the SSH private host key files have mode 0600 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------- 1 root ssh_keys 668 Nov 28 06:43 ssh_host_dsa_key -rw------- 1 root ssh_keys 582 Nov 28 06:43 ssh_host_key -rw------- 1 root ssh_keys 887 Nov 28 06:43 ssh_host_rsa_key If any file has a mode more permissive than 0600, this is a finding.

Check Text ( C-23574r792801_chk )

Verify the SSH private host key files have mode 0600 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------- 1 root ssh_keys 668 Nov 28 06:43 ssh_host_dsa_key
-rw------- 1 root ssh_keys 582 Nov 28 06:43 ssh_host_key
-rw------- 1 root ssh_keys 887 Nov 28 06:43 ssh_host_rsa_key

If any file has a mode more permissive than 0600, this is a finding.

Fix Text (F-23563r792802_fix)
Configure the mode of SSH private host key files under "/etc/ssh" to "0600" with the following command: # chmod 0600 /path/to/file/ssh_host*key