Sven Jaschen received a sentence of one year and nine months on probation - meaning he will walk free. The four-day trial in Verden, North Germany looked into one of the biggest internet attacks of its kind. He avoided jail because he released all of his worms before his 18th birthday and has been tried as a minor.
"Jaschan avoided a jail sentence by the skin of his teeth because he was arrested within days of his 18th birthday," continued Cluley. "In many ways, Sven Jaschan was lucky that the police caught him when they did. Nevertheless, his name will always be associated with some of the biggest viruses in the history of the internet."
The Sasser worm attacked millions of computers around the world, while versions of the Netsky virus still continue to spread via email. The virus accounts for over 25 percent of all virus reports in the first six months of this year. The Netsky-P worm, which poses as a Harry Potter computer game, is the second most widespread virus of the year to date.
"Even a year after his arrest, it is more likely that you will be infected by a worm written by Sven Jaschan than any other virus author," said Graham Cluley, senior technology consultant for Sophos.
Cluley said that organized crime gangs are becoming an increasing threat and they should be dealt the harsh sentences "over and above the dumb teenagers".
Prosecutors charged Jaschan with computer sabotage in September 2004. He pleaded guilty to data manipulation, computer sabotage and interfering with public corporations.