Jason Milmont pleaded guilty last year to creating the Nugache worm, which infected between 5,000 and 15,000 computers in 2007. He used the worm to build a botnet of infected computers and stole online account information and credit card numbers from his victims, according to his plea agreement. He then used the information to buy goods and services, court fillings say.

Milmont had been facing five years in prison when he was sentenced Tuesday in U.S. District Court in Cheyenne. In addition to the probation, he was ordered to pay US$36,859 restitution in monthly payments of $250, according to court documents.

Judge William Downes "told the young man that he had quite a bit of talent and hoped he would use it for good," according to John Powell, a spokesman for the U.S. Attorney's Office in Cheyenne. Milmont was initially charged in California but the case was transferred to Wyoming for sentencing, Powell said.

Milmont was just a teenager when he created his botnet. He used advanced cryptographic techniques and created a novel way of controlling the botnet via peer-to-peer networks, said Dave Dittrich, a researcher with the University of Washington. "It was a completely different way of controlling a bunch of computers and makes it much harder to find the person who was controlling them," he said.

Other botnets, including Conficker and Storm, have adopted similar techniques, he said, adding, "in some ways, Nugache is more successful in using peer-to-peer for command and control than Conficker."