I'm more of an MSDN user than Technet, coming at architecture from a solutions development background, but this article interested me as a nice reminder of some of the common doors that are often left open to intruders - http://www.microsoft.com/technet/technetmag/issues/2005/01/AnatomyofaHack/default.aspx. By the way, if you haven't already bought Writing Secure Code 2nd Edition (ISBN 0-7356-1722-8) you should :-)