"The Storm Worm [botnet] has the ability to defend itself," Sop explains. "When you scan it, it will tell another portion of the botnet to DDoS you." In a DDoS, or distributed-denial-of-service attack, a bot herder instructs some or all of the botnet to send a flood of garbage data to a particular victim. And often that flood is enough to knock a Web site offline, or to take down a researcher's Internet connection.
Storm is the only botnet Sop knows of with this kind of automated self-defense. What's more, it's sneaky about how it executes that defense. It won't launch the attack from the same machines that are scanned, or even ones with similar IP addresses, since that would make the attack's cause immediately apparent. Instead, it passes along the researcher's location to other parts of the Storm botnet, so the DDoS attack appears to come from somewhere else.
The Storm Worm has become so ubiquitous, it's even a star on YouTube, where an F-Secure video that shows the worm's spread around the globe has been viewed more than 850,000 times. (Check out the comments, where you'll find some viewers who are convinced that the worm was created by extraterrestrial forces.)
To help ensure that you don't become the next cog of the vast Storm Worm wheel, use a good antivirus program, and keep your applications up-to-date. The Storm Worm and other such malware frequently exploit known holes in old versions of software such as Internet Explorer, Firefox, QuickTime, and even WinZip to infect PCs.
Also, exercise extreme caution with any unsolicited e-mail, even if it appears to come from someone you know. And finally, to help determine whether your computer might have already joined the ranks of the living dead, see ."