"Once you close one vulnerability you move the attack surface to another part," he said. Jagex's efforts to tackle farming had removed 90% of the problem, said Mr Gerhard.
"They were going directly after the user credentials and trying to get at the wealth that way," he said.
"Players invest years of time and effort into developing their buy runescape character so the theft of a Runescape account shouldn't be treated differently to the theft of any other valuable possessions such as a games console, television or car," he said.
Alisdair Faulkner, a computer security expert at ThreatMetrix, said it was seeing many more hi-tech thieves turn to stealing virtual rather than real goods.
Virtual goods were much easier to launder and dispose of than tangible items such as flat screens and computers, he said. It was a particular problem in