Vulnerability Discussion

Changes to any software components can have significant effects on the overall security of the operating system. This requirement ensures the software has not been tampered with and that it has been provided by a trusted vendor.

Accordingly, patches, service packs, device drivers, or operating system components must be signed with a certificate recognized and approved by the organization.

Verifying the authenticity of the software prior to installation validates the integrity of the patch or upgrade received from a vendor. This verifies the software has not been tampered with and that it has been provided by a trusted vendor. Self-signed certificates are disallowed by this requirement. The operating system should not have to verify the software again. This requirement does not mandate DOD certificates for this purpose; however, the certificate used to verify the software must be from an approved Certificate Authority (CA).

Check

Verify the operating system prevents the installation of patches, service packs, device drivers, or operating system components from a repository without verification that they have been digitally signed using a certificate that is recognized and approved by the organization.

Check if YUM is configured to perform a signature check on local packages with the following command:

$ sudo grep -i localpkg_gpgcheck /etc/dnf/dnf.conf

localpkg_gpgcheck =True

If "localpkg_gpgcheck" is not set to either "1", "True", or "yes", commented out, or is missing from "/etc/dnf/dnf.conf", this is a finding.

Fix

Configure the operating system to remove all software components after updated versions have been installed.

Set the "localpkg_gpgcheck" option to "True" in the "/etc/dnf/dnf.conf" file:

localpkg_gpgcheck=True