http://zdnet.com.com/2100-1105_2-5062364.html

Dubbed "MSBlast" by its author, the worm is spreading quickly, according to an initial analysis posted to the Internet Storm Center, a digital threat-tracking site. Ever since mid-July, when Microsoft announced a vulnerability in a widespread component of Windows, security experts have been waiting for some online vandal to create a worm that takes advantage of it.

http://zdnet.com.com/2100-1105_2-506...tml?tag=fdfeed

The worm, which security experts believe started spreading early Monday, scans for vulnerable computers so widely that an unpatched Windows XP computer on the Internet could be infected in as little as 25 minutes, according to Symantec studies.