Aaron Caffrey of Shaftesbury, Dorset admitted that he was part of a group of hackers called Allied Haxor Elite, and that his computer had been used to launch a denial of service attack on the Port of Houston's computer network in September 2001.
But in his defence, Caffrey said that he had never illegally hacked into a computer and that the attack against the Port of Houston's system was launched by hackers using a Trojan, and that the Trojan was also used to plant evidence of the attack on his machine.
A Trojan, or Trojan horse, is a program that is installed onto a computer without the owner's knowledge, usually by deceiving the owner about what he or she is getting when opening an e-mail attachment or downloading a file. Once installed, the Trojan horse can carry out malicious acts or give another user remote control of the target computer.
However, according to reports, a forensic examination of Caffrey's PC found attack tools but no trace of Trojan infection. So Caffrey had to convince the jury that a Trojan could wipe itself, arguing against prosecution claims that no such technology existed. As news site TheRegister.co.uk observes, the case potentially opens the floodgates for Trojan defences.
ComputerWeekly.com also notes that, during the trial, police and IT security professionals expressed concern that language used in the Computer Misuse Act of 1990 does not criminalise denial of service attacks.