U.S. District Judge Marsha Pechman added three years of supervision after his release, and ordered him to perform 100 hours of community service. A restitution hearing will be held next month to decide what amount Parson, 19, must pay Microsoft and several individuals to make up damages for his worm.
Pechman laid blame on Parson's parents for the crime. "I didn't see any parent standing there saying, 'It's not a healthy thing to lock yourself in a room and create your own reality,'" Pechman was quoted as saying in the Seattle Post-Intelligencer. The Internet "has created a dungeon for people who have mental illnesses or people who are lonely," Pechman added.
According to federal investigators, Parson's MSBlast.b worm caused $1.2 million in damages and infected nearly 50,000 systems in the late summer of 2003.
Prosecutors had asked for the maximum sentence struck during an earlier plea agreement, 37 months, while Parson's attorneys had asked Pechman to reduce the sentence to just six months in prison with three years of probation.
Instead, the judge gave Parson 18 months, the minimum in the plea agreement range.
Assistant U.S. Attorney Annette Hays, whose office prosecuted the case, was quoted by the Post-Intelligencer as reacting with, "The defendant has a long and well-documented history of malicious actions over the Internet. Clearly he knew that what he was doing was wrong."
Parson has also admitted to attacking the Recording Industry Association of America (RIAA) Web site.
The Hopkins, Minn. resident will serve his sentence in a low-security facility.