Who at the time a server with Windows is the operating system should definitely update.
As announced by Microsoft, there is a critical security gap in the Windows Server versions from Windows Server 2003 and in the Windows Desktop versions from Vista. The corresponding update has been released on the night of November 19 and should be strictly carried out.
The error allows the remote attacker to gain administrator privileges authentication system Kerberos to and thus all servers that are located in a network attack. Please carry out the update as soon as possible to protect your servers.
You can find more information directly from Microsoft through the official link: https://support.microsoft.com/kb/3011780
We wish you a nice weekend.