From Brian Krebs’ “Atrivo Shutdown Hastened Demise of Storm Worm” (The Washington Post: 17 October 2008):
The infamous Storm worm, which powered a network of thousands of compromised PCs once responsible for sending more than 20 percent of all spam, appears to have died off. Security experts say Storm’s death knell was sounded by the recent shutdown of Atrivo, a California based ISP that was home to a number of criminal cyber crime operations, including at least three of the master servers used to control the Storm network.
Three out of four of [Storm’s] control servers were located at Atrivo, a.k.a. Intercage, said Joe Stewart, a senior security researcher with Atlanta based SecureWorks who helped unlock the secrets of the complex Storm network. The fourth server, he said, operated out of Hosting.ua, an Internet provider based in the Ukraine.
Stewart said the final spam run blasted out by Storm was on Sept. 18.Three days later, Atrivo was forced off the Internet after its sole remaining upstream provider — Pacific Internet Exchange (PIE) — decided to stop routing for the troubled ISP. In the weeks leading up to that disconnection, four other upstream providers severed connectivity to Atrivo, following detailed reports from Security Fix and Host Exploit that pointed to a massive amount of spam, malicious software and a host of other cyber criminal operations emanating from it.
Stewart said spam sent by the Storm network had been steadily decreasing throughout 2008, aided in large part by the inclusion of the malware in Microsoft’s malicious software removal tool, which has scrubbed Storm from hundreds of thousands of PCs since last fall. Stewart said it’s impossible to tell whether the Storm worm was disrupted by the Atrivo shutdown or if the worm’s authors pulled the plug themselves and decided to move on. But at least 30,000 systems remain infected with the Storm malware.