The forces of evil have produced a devilish tool whereby spam can be sent to thousands of Windows users in minutes, in the guise of system alerts. This was brought to our attention by reader Mike MacNeill, who sent us a screenie of a Windows system alert offering him the university diploma of his dreams with "no required tests, classes, books or interviews," in the classic manner.

The scam is the brainchild of an outfit called DirectAdvertiser, and leverages the Windows RPC (Remote Procedure Call) function. I downloaded the demo version and played around for a while. My results may not be entirely accurate because I didn't use the full, $700 version, and because I used it on my own network behind a firewall. However, running Ethereal on the box and trying it out revealed packets destined for ports 135 (DCE/RPC), 137 (NetBIOS name service) and 138 (NetBIOS UDP) on the target.

So we have here essentially a NetBIOS attack tool. It's capable of attacking entire IP ranges, but will not (the company says) get past a firewall or provide a hyperlink in the alert to the attacker's commercial Web site. The latter shortcoming is currently being addressed, the company says.

The quickest way to defeat it is simply to shut off Windows Messenger (not the MSN Messenger IM client), so long as it's not needed by other applications. Otherwise port 135 UDP and TCP can be filtered. If neither of these solutions is suitable, the company invites you to share with them "any questions, comments, or suggestions that you may have" at this e-mail address.