A recent flaw in some of Microsoft's computer programs left many PC users vulnerable, and computer hackers have taken full advantage.
Microsoft experts spotted flaws in its programs weeks ago, flaws that could allow hackers to take complete control of computer systems. They issued warnings, and offered a "patch" to fix the flaws. But these measures were not enough to prevent malicious worms, known as Zotob and Rbot, from shutting down computers running Microsoft's Windows 2000 operating system.
"So if I'm sitting at home and I'm oblivious to Microsoft having issued this warning, this patch," explains former FBI Internet Chief Michael Vatis, "[if] I was on vacation or I just wasn't paying attention, my machine could be vulnerable to that worm."
Experts say the worms are hitting organizations rather than individuals. Large companies are most vulnerable to hackers, because software updates can take days, or even weeks, to install on large systems. So far, the victims have been U.S. corporations, such as Chrysler, ABC and The New York Times.
But as Oliver Friedrichs of Symantec, a company that makes anti-virus software, explains, the worms could easily spread beyond the U.S. "This particular threat is not really regional specific," says Mr. Friedrichs. "It's just as likely to affect Asia and Europe as it is the United States."
A computer worm is similar to a computer virus. The difference is, a virus works by attaching itself to another computer program. A worm is self-contained and does not need another program to work. This characteristic makes the worm far more dangerous than past computer viruses.
"It actually can attack your computer without you having to open your e-mail or interact with your computer in any way," explains Mr. Friedrichs. "Essentially, by being connected to your network or to the Internet, you can become infected."
Computer hackers taking advantage of the security hole can access remotely the Microsoft 2000 operating system's "Plug and Play" feature. The security breach is dangerous enough for Microsoft to rate acquiring its patch as "critical", its highest designation.
Experts say improved security can be expected on newer software.