Remote SMB Exploit: Crashing Windows 7 and Server 2008

Python code was posted today by Laurent Gaffie on his blog, demonstrating a much too easy way to remotely crash a Windows 7 or Windows Server 2008 machine. The crash is caused by sending a NetBIOS header which specifies that the SMB packet is 4 bytes smaller or larger than it actually is. In this code sample below, you can see that the header has the length of the packet set to 9a rather than 9e (4 bytes smaller).