STIGUI
V-221859CAT II — Medium severitySV-221859r991589_rule

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

Rule version OL07-00-040420 · STIG v3 · 2025-05-08

Discussion

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

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

Identifiers

Group ID
V-221859
Group title
SRG-OS-000480-GPOS-00227
Rule ID
SV-221859r991589_rule
Check ID
C-23574r880577_chk
Fix ID
F-23563r880578_fix