The most ferocious threats today are ''network worms,'' which exploit a particular flaw in a software product (often one by Microsoft). The author of Slammer, for example, noticed a flaw in Microsoft's SQL Server, an online database commonly used by businesses and governments. The Slammer worm would find an unprotected SQL server, then would fire bursts of information at it, flooding the server's data ''buffer,'' like a cup filled to the brim with water. Once its buffer was full, the server could be tricked into sending out thousands of new copies of the worm to other servers. Normally, a server should not allow an outside agent to control it that way, but Microsoft had neglected to defend against such an attack. Using that flaw, Slammer flooded the Internet with 55 million blasts of data per second and in only 10 minutes colonized almost all vulnerable machines. The attacks slowed the 911 system in Bellevue, Wash., a Seattle suburb, to such a degree that operators had to resort to a manual method of tracking calls.
Philet0ast3r said he isn't interested in producing a network worm, but he said it wouldn't be hard if he wanted to do it. He would scour the Web sites where computer-security professionals report any new software vulnerabilities they discover. Often, these security white papers will explain the flaw in such detail that they practically provide a road map on how to write a worm that exploits it. ''Then I would use it,'' he concluded. ''It's that simple.''
Computer-science experts have a phrase for that type of fast-spreading epidemic: ''a Warhol worm,'' in honor of Andy Warhol's prediction that everyone would be famous for 15 minutes. ''In computer terms, 15 minutes is a really long time,'' says Nicholas Weaver, a researcher at the International Computer Science Institute in Berkeley, who coined the Warhol term. ''The worm moves faster than humans can respond.'' He suspects that even more damaging worms are on the way. All a worm writer needs to do is find a significant new flaw in a Microsoft product, then write some code that exploits it. Even Microsoft admits that there are flaws the company doesn't yet know about.
