SLEM 5 SSH daemon private host key files must have mode 640 or less permissive.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-261294	SRG-OS-000480-GPOS-00227	SLEM-05-232045	SV-261294r996359_rule	2024-06-04	1

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

ℹ️ Check
Verify SLEM 5 SSH daemon private host key files have mode "640" or less permissive. The following command will find all SSH private key files on the system with the following command: > sudo find / -name 'ssh_hostkey' -exec ls -lL {} \; Check the mode of the private host key files under "/etc/ssh" file with the following command: > find /etc/ssh -name 'ssh_host*key' -exec stat -c "%a %n" {} \; 640 /etc/ssh/ssh_host_rsa_key 640 /etc/ssh/ssh_host_dsa_key 640 /etc/ssh/ssh_host_ecdsa_key 640 /etc/ssh/ssh_host_ed25519_key If any file has a mode more permissive than "640", this is a finding.

ℹ️ Check

Verify SLEM 5 SSH daemon private host key files have mode "640" or less permissive. The following command will find all SSH private key files on the system with the following command: > sudo find / -name '*ssh_host*key' -exec ls -lL {} \; Check the mode of the private host key files under "/etc/ssh" file with the following command: > find /etc/ssh -name 'ssh_host*key' -exec stat -c "%a %n" {} \; 640 /etc/ssh/ssh_host_rsa_key 640 /etc/ssh/ssh_host_dsa_key 640 /etc/ssh/ssh_host_ecdsa_key 640 /etc/ssh/ssh_host_ed25519_key If any file has a mode more permissive than "640", this is a finding.

✔️ Fix
Configure the mode of SLEM 5 SSH daemon private host key files under "/etc/ssh" to "640" with the following command: > sudo chmod 640 /etc/ssh/ssh_host*key