The SSH public host key files must have mode 0644 or less permissive.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-72255	RHEL-07-040410	SV-86879r1_rule		Medium

Description
If a public host key file is modified by an unauthorized user, the SSH service may be compromised.

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

Details

Check Text ( C-72489r1_chk )
Verify the SSH public host key files have mode "0644" or less permissive. Note: SSH public key files may be found in other directories on the system depending on the installation. The following command will find all SSH public key files on the system: # find /etc/ssh -name '*.pub' -exec ls -lL {} \; -rw-r--r-- 1 root wheel 618 Nov 28 06:43 ssh_host_dsa_key.pub -rw-r--r-- 1 root wheel 347 Nov 28 06:43 ssh_host_key.pub -rw-r--r-- 1 root wheel 238 Nov 28 06:43 ssh_host_rsa_key.pub If any file has a mode more permissive than "0644", this is a finding.

Check Text ( C-72489r1_chk )

Verify the SSH public host key files have mode "0644" or less permissive.

Note: SSH public key files may be found in other directories on the system depending on the installation.

The following command will find all SSH public key files on the system:

# find /etc/ssh -name '*.pub' -exec ls -lL {} \;

-rw-r--r-- 1 root wheel 618 Nov 28 06:43 ssh_host_dsa_key.pub
-rw-r--r-- 1 root wheel 347 Nov 28 06:43 ssh_host_key.pub
-rw-r--r-- 1 root wheel 238 Nov 28 06:43 ssh_host_rsa_key.pub

If any file has a mode more permissive than "0644", this is a finding.

Fix Text (F-78609r1_fix)
Note: SSH public key files may be found in other directories on the system depending on the installation. Change the mode of public host key files under "/etc/ssh" to "0644" with the following command: # chmod 0644 /etc/ssh/*.key.pub