I was just reading the programming blog at reddit, as I often do, and then I stumpled upon this title:

Remember the good old days of the 1990s, when you could teardrop attack any Windows user who'd annoyed you and bluescreen them? Microsoft reintroduces this popular feature in Windows 7, courtesy the rewritten TCP/IP and SMB2 stacks.

The problem is that Windows 7 (and Vista) now ships with a new version of SMB (version 2). Here it is possible to send a (special) malformed SMB header to a target computer, and thereby making it crash with a B.S.O.D. The only requirement for the target system is that it has to have SMB2 enabled.

As the actual scary part; there is no patch to fix this yet.. So don't use SMB2 until then.

Here is the URL to the article: http://seclists.org/fulldisclosure/2009/Sep/0039.html