The Storm worm is fighting back against security researchers that seek to destroy it and has them running scared, Interop New York show attendees heard this week.

The worm can figure out which users are trying to probe its command-and-control servers, and it retaliates by launching DDoS attacks against them, shutting down their Internet access for days, says Josh Korman, host-protection architect for IBM/ISS, who led a session on network threats.

"As you try to investigate [Storm], it knows, and it punishes," he says. "It fights back."

As a result, researchers who have managed to glean facts about the worm are reluctant to publish their findings. "They're afraid. I've never seen this before," Korman says. "They find these things but never say anything about them."

And not without good reason, he says. Some who have managed to reverse engineer Storm in an effort to figure out how to thwart it have suffered DDoS attacks that have knocked them off the Internet for days, he says.

As researchers test their versions of Storm by connecting to Storm command-and-control servers, the servers seem to recognize these attempts as threatening. Then either the worm itself or the people behind it seem to knock them off the Internet by flooding them with traffic from Storm's botnet, Korman says.

A recently discovered capability of Storm is its ability to interrupt applications as they boot up and either shut them down or allow them to appear to boot, but disable them. Users will see that, say, antivirus is turned on, but it isn't scan for viruses, or as Korman puts it, it is brain-dead. "It's running, but it's not doing anything. You can brain-dead anything," he says.

The worm has created a botnet of slave machines whose latent size and power is unknown. The number of infected machines available to launch spam and DoS attacks is estimated from hundreds of thousands to 50 million. Korman says he believes it's between 6 million and 15 million.

One intimidating aspect of the botnet the worm commands is that it is used infrequently, indicating that it is for sale or lease to what he terms "profit nation" -- computer hackers who do their work for money not fame. The potential exists for the botnet to be used by political entities for cyberterror attacks, he says.

"It's getting more serious the more I look at it," Korman says. "I'm more concerned not so much about where Storm is today, but where it's going."

Still, the power of Storm, also known as Peacomm, is still hotly debated. Earlier this week another expert said the worm had pretty much run its course and was subsiding.