Kerberos in Microsoft Windows Vista SP2 Windows Server 2008 SP2 and R2 SP1 Windows 7 SP1 Windows 8.1 Windows Server 2012 Gold and R2 and Windows 10 Gold and 1511 does not properly validate password changes which allows remote attackers to bypass authentication by deploying a crafted Key Distribution Center (KDC) and then performing a sign-in action aka \Windows Kerberos Security Feature Bypass.\