Microsoft has released a free beta version of Attack Surface Analyzer
 

The tool is currently used internally at Microsoft to catalog and compare the various changes made to Windows during software installations. Created by Microsoft’s Security Engineering Group, the tool takes snapshots of an organization’s system and compares (“diffing�) these to identify changes. The tool does not analyze a system based on signatures or known vulnerabilities; instead, it looks for classes of security weaknesses as applications are installed on the Windows operating system.

http://www.microsoft.com/downloads/e...displaylang=en