Source routing must be configured to the highest protection level to prevent Internet Protocol (IP) source routing. GROUP ID:V-224917 RULE ID:SV-224917r991589 Configuring the system to disable IP source routing protects against spoofing.
Solution
Configure the policy value for Computer Configuration >> Administrative Templates >> MSS (Legacy) >> 'MSS: (DisableIPSourceRouting) IP source routing protection level (protects against packet spoofing)' to 'Enabled' with 'Highest protection, source routing is completely disabled' selected. This policy setting requires the installation of the MSS-Legacy custom templates included with the STIG package. 'MSS-Legacy.admx' and 'MSS-Legacy.adml' must be copied to the \Windows\PolicyDefinitions and \Windows\PolicyDefinitions\en-US directories respectively.