When the WDigest Authentication protocol is enabled, plain text passwords are stored in the Local Security Authority Subsystem Service (LSASS) exposing them to theft. WDigest is disabled by default in Windows 10. This setting ensures this is enforced.
Configure the policy value for Computer Configuration >> Administrative Templates >> MS Security Guide >> "WDigest Authentication (disabling may require KB2871997)" to "Disabled".
The patch referenced in the policy title is not required for Windows 10.
This policy setting requires the installation of the SecGuide custom templates included with the STIG package. "SecGuide.admx" and "SecGuide.adml" must be copied to the \Windows\PolicyDefinitions and \Windows\PolicyDefinitions\en-US directories respectively.