From TechRepublic:
A federal judge on Friday sentenced a 19-year-old Minnesota man to 18 months in prison for unleashing a variant of the MSBlast worm.
Jeffrey Lee Parson, 19, of Minnesota was ordered to serve his time in a minimum security prison and participate in 10 months of community service.
FBI agents arrested Parson at his home in Hopkins, Minn., in August 2003, just two weeks after his ‘MSBlast.B’ variant began to tunnel into Microsoft Windows-based computers. His variant of the worm infected approximately 48,000 computers that had not yet applied an earlier released patch.