Microsoft's Attack Surface Analyzer

Microsoft released some recent updates to its secure development life-cycle tools recently, and showed some of the Enhancements at Black Hat DC . These tools are not necessarily limited to .Net, but if your a .NET developer, I highly recommend that . take a closer look at them.
for Exp... The Attack Surface Analyzer compares the state of your system before and after you install software to determine the impact your software has on the system, what resources it depends on and what changes it makes. It will also enumerate possible security issues. good step in the right direction...

Microsoft SDL blog article has more details.
http://www.microsoft.com/security/sdl/getstarted/tools.aspx
http://blogs.msdn.com/b/sdl/archive/2011/01/17/announcing-attack-surface-analyzer.aspx