Owen Walker was convicted in the Thames District Court yesterday of botnet crime. Photo / Alan Gibson

Owen Walker was convicted in the Thames District Court yesterday of botnet crime. Photo / Alan Gibson

Self-taught Whitianga computer whiz Owen Walker has admitted being involved in international botnet conspiracies.

Eighteen-year-old Walker, known in cyberspace as Akill, cut a slight, pale figure as he stood in the Thames District Court yesterday and listened to his lawyer enter guilty pleas to six charges including dishonest use of a computer, damaging a computer system and possessing software for committing crime.

The crimes carry sentences of up to seven years but there are indications he may serve a community-based sentence.

Walker's appearance before Judge Arthur Tompkins was over in minutes but a police summary of facts handed to the judge details his superhacking.

Home-schooled in his high-school years and with no formal training in computers, Walker taught himself computer programming and encryption.

He met like-minded people through chat rooms and started experimenting with malware, which allowed him to infect and remotely control computers, using them as robots, or bots.

A collection of bots is called a botnet and the person who controls them is a botherder.

Walker created his own bot code, which police say is "considered by international cyber crime investigators to be among the most advanced bot programming encountered".

Walker's code was protected from discovery, spread automatically and could identify and destroy rival bot codes.

It automatically disabled any anti-virus software on an infected computer, and prevented the software being updated.

The computer owner could not tell the anti-virus software was not working.

The code could also scan for information that could be used to conduct fraudulent financial transactions, but there is no evidence this was ever done.

Police say it may never be known how many computers Walker controlled but it ran to tens of thousands.

He controlled them through servers outside New Zealand either by leasing space or by accessing them illegally.

In February 2006, Walker worked with University of Pennsylvania student Ryan Goldstein and attacked a university computer server.