Remote Desktop Session Host (RDSH) in Remote Desktop Protocol (RDP) through 8.1 in Microsoft 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 does not properly verify certificates, which allows man-in-the-middle attackers to spoof clients via a crafted certificate with valid Issuer and Serial Number fields, aka "Remote Desktop Session Host Spoofing Vulnerability."