The SSH private host key files must have mode 0600 or less permissive.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-72257	RHEL-07-040420	SV-86881r1_rule		Medium

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

STIG	Date
Red Hat Enterprise Linux 7 Security Technical Implementation Guide	2017-07-08

Details

Check Text ( C-72491r1_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: # find / -name 'ssh_hostkey' Check the mode of the private host key files under "/etc/ssh" file with the following command: # ls -lL /etc/ssh/*key -rw------- 1 root wheel 668 Nov 28 06:43 ssh_host_dsa_key -rw------- 1 root wheel 582 Nov 28 06:43 ssh_host_key -rw------- 1 root wheel 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-72491r1_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:

# find / -name '*ssh_host*key'

Check the mode of the private host key files under "/etc/ssh" file with the following command:

# ls -lL /etc/ssh/*key
-rw------- 1 root wheel 668 Nov 28 06:43 ssh_host_dsa_key
-rw------- 1 root wheel 582 Nov 28 06:43 ssh_host_key
-rw------- 1 root wheel 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-78611r3_fix)
Configure the mode of SSH private host key files under "/etc/ssh" to "0600" with the following command: # chmod 0600 /etc/ssh/ssh_host*key