Experts from across the security industry collaborated this week to quarantine more than 110,000 Microsoft Windows PCs that were infected with the Khelios worm, a contagion that forces infected PCs to blast out junk email advertising rogue Internet pharmacies.
Most botnets are relatively fragile: If security experts or law enforcement agencies seize the Internet servers used to control the zombie network, the crime machine eventually implodes. But Khelios (a.k.a. “Kelihos”) was built to withstand such attacks, employing a peer-to-peer structure not unlike that used by popular music and file-sharing sites to avoid takedown by the music and entertainment industry.