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

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-221859	OL07-00-040420	SV-221859r880579_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	2022-12-06

Details

Check Text ( C-23574r880577_chk )
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.

Check Text ( C-23574r880577_chk )

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 Text (F-23563r880578_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