Two new Mydoom variants launch attack

COMMENTARY: Two new electronic worms emerged this week, both of which seek to exploit Windows-based PCs that the original Mydoom email virus have already infected.

Like the weakened Mydoom.B email virus variant, however, both of the new worms are categorised as low-risk by security researchers, who note that the worms have compromised few users. And unlike Mydoom.A and Mydoom.B, instead of spreading through email attachments the new attacks prowl the internet looking for Mydoom-compromised computers that haven't yet been inoculated.

The first worm, Doomjuice, attempts to seize infected computers and use them for Distributed Denial of Service (DDoS) attacks on Microsoft's website. The second worm, Deadhat, removes the Mydoom virus and waits for further instructions, presumably from yet another worm; Deadhat got its start on the Soulseek file-sharing system.

The anti-virus experts at Network Associates note that although Doomjuice has had a bit of success, largely because some people didn't realise they were infected with Mydoom, neither worm is expected to make much of an impact.

On the other hand, Doomjuice and Deadhat prove that earlier thinking about electronic-attack flare-ups might be out-of-date.

"Computer users cannot treat the risk from malware as an episodic situation based on a specific virus event," Ian Hameroff, a security strategist at Computer Associates, said.

"Instead, they need to treat the cause, be it social engineering or outdated virus definition updates, not an individual flare-up." Microsoft denied reports that Deadhat was responsible for intermittent problems on its website this week.