Teenager cleared of email attack charge

A British teenager has been cleared of launching a denial-of-service (DoS) attack against his former employer, in a ruling that delivers another blow to the Computer Misuse Act.

Sitting at Wimbledon Magistrates Court, District Judge Kenneth Grant ruled that the youth, who can't be named for legal reasons, had not broken the CMA, under which he was charged. He was accused of sending five million emails to his ex-employer, causing the firm's email server to crash.

The CMA, which was introduced in 1990, explicitly outlaws the 'unauthorised access' and 'unauthorised modification' of computer material. Section 3, under which he was charged, concerns unauthorised data modification and tampering with systems.

The defendant was not called into the witness box during the trial, so he never confirmed whether or not the attack had taken place. The defence counsel argued that sending a flood of unsolicited emails would not cause unauthorised access or modification, as the email server was set up for the purpose of receiving emails.

Judge Grant told the court that "the computer world has considerably changed since the 1990 Act", and that there was little legal precedent to refer back to. He then ruled that DoS attacks were not illegal under the CMA.

In a written ruling, Judge Grant said: "In this case the individual emails caused to be sent each caused a modification which was in each case an 'authorised' modification. Although they were sent in bulk resulting in the overwhelming of the server, the effect on the server is not a modification addressed by section 3 [of the CMA]."

"On the narrow issue of an authorised or unauthorised modification, I concluded that no reasonable tribunal could conclude that the modification caused by the emails sent by the defendant were unauthorised within the meaning of section 3," Grant added.

Peter Sommer, expert witness for the defence, called for the CMA to be revised in the light of this trial.

"This is an interesting result, which highlights the need for reform of the CMA," Sommer said.

The teenager greeted the news with relief, although an appeal by the prosecution is still possible.

"I feel very happy. This has been going on for two years. At the moment, this is no longer hanging over my head," he told ZDNet UK.