The Group Policy Security Configuration policy implementation in Microsoft Windows Server 2003 SP2 Windows Vista SP2 Windows Server 2008 SP2 and R2 SP1 Windows 7 SP1 Windows 8 Windows 8.1 Windows Server 2012 Gold and R2 and Windows RT Gold and 8.1 allows man-in-the-middle attackers to disable a signing requirement and trigger a revert-to-default action by spoofing domain-controller responses aka \Group Policy Security Feature Bypass Vulnerability.\