The Kerberos Key Distribution Center (KDC) in Microsoft Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, and Windows Server 2012 Gold and R2 allows remote authenticated domain users to obtain domain administrator privileges via a forged signature in a ticket, as exploited in the wild in November 2014, aka "Kerberos Checksum Vulnerability."
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2014/ms14-068
http://www.us-cert.gov/ncas/alerts/TA14-323A
http://marc.info/?l=bugtraq&m=142350249315918&w=2
http://blogs.technet.com/b/srd/archive/2014/11/18/additional-information-about-cve-2014-6324.aspx