Researchers at the SANS Internet Storm Center have reported finding exploit code that will crash Vista (SP 1 & 2) and Windows 7. It also could affect Windows Server 2008. The vulnerability it exploits is in the Windows Samba file-sharing mechanism.
A malicious agent need only send one malicious packet to a machine through port 445 to bring on the BSOD, they said. Port 445 is used for file sharing.
Obviously, a work-around is to shut port 445 at the firewall.
Since home users are inclined to use file-sharing and not to have firewalls, there are a lot of vulnerable machines out there. The vulnerability can be used for denial-of-service attacks at this point, but those rarely make money. We can be sure the dark side is working hard to figure out how to “monetize” it.
SANS Internet Storm Center note.