Jeanson James Ancheta used the compromised PCs to display cash-generating adverts and rent them out to hackers to send spam campaigns and launch DoS attacks.
Ancheta was sentenced to 57 months in prison, making this the longest ever imprisonment for a case involving the spreading of malware. He was also ordered to pay $15,000 to the military organizations whose computers were hit by his attacks.
The 21-year-old, from Los Angeles, profited by installing adware on a network of innocent third-party compromised computers. According to prosecutors, some of the computers attacked were at the Weapons Division of the U.S. Naval Air Warfare Center in China Lake, Calif., and at the U.S. Department of Defense.
Ancheta admitted advertising his botnets online via an IRC channel named "botz4sale," selling access to software that could remotely control computers to deliver spam and launch DDoS attacks against websites. Websites hit by a DDoS attack could then be blackmailed into paying large sums of money to have public access to the sites restored.
Ancheta made more money by installing adware on the zombie computers - using the proceeds to pay for computer servers to carry out additional attacks, new clothes and a BMW luxury car.
"The U.S. authorities will be delighted to have won this victory in the fight against serious internet crime. It gives the man in the street some insight into the fortunes that can be made and the sheer scale of the zombie problem," said Graham Cluley, senior technology consultant for Sophos. "But this remains the tip of the iceberg. Ancheta was based in California, making him within easy reach of investigators. Others running bot networks may be based anywhere in the world, meaning that to truly crack this problem more international cooperation is required."