Sven Jaschan, a 19-year-old German, is accused of creating and distributing the worm, which infected thousands of computers worldwide in 2004. He was uncovered after Microsoft offered a $250,000 bounty for information that led to the capture of the internet's most damaging virus.
Since the allegations were made, Jaschan has sought to improve his reputation by working for German firm Securepoint. As SC reported late last year, the hiring of such a high profile virus writer divided opinion within the information security community.
The spread of the Sasser worm caused numerous high profile groups, including the European Commission, to be infected and millions of dollars lost. Several networks broke down completely. Its success also encouraged companies to improve their security.
If found guilty Jaschan faces a jail sentence of up to five years and will be confirmed responsible for 50 percent of last year's virus infections.
Leading up to July's case, over 140 complaints were filed against Jaschan.