Sven Jaschan, 19, a programmer on trial for writing the Sasser computer worm which wreaked havoc in big businesses and homes across the world last year has confessed. During his trial, Jaschan has admitted to data manipulation, computer sabotage and interfering with public corporations, in a case of one of the biggest malware attacks on the Internet to date. A verdict is expected on Thursday.

Prosecutors said damages amounting to some 130,000 euros ($154,600) had so far been reported by victims of the worm, but the figure could spiral into millions if everyone affected worldwide were to report financial losses caused by the worm.

How the 19-year-old was expected to pay such compensation was not immediately clear.

Jaschan, described by authorities as a "computer freak," was identified as the author after Microsoft offered a reward of $250,000 for information leading to his arrest.

It is believed he began creating programs, including the Netsky virus, to seek out and destroy other viruses.