The Red Hat Enterprise Linux operating system must be configured so that the SSH public host key files have mode 0644 or less permissive.

From Red Hat Enterprise Linux 7 Security Technical Implementation Guide

Associated with: CCI-000366

SV-86879r2_rule The Red Hat Enterprise Linux operating system must be configured so that the SSH public host key files have mode 0644 or less permissive.

Vulnerability discussion

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

Check content

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

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

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