Security experts have intercepted a Trojan designed to steal usernames and passwords from players of the popular online multiplayer game Lineage.

The game involves players wandering around an online landscape, collecting magical items and slaying monsters or sometimes each other. The virus code, named LegMir-Y, sits on the host PC and attempts to steal players' login details.

"It is more and more common for the analysts in our virus lab to discover that, as well as causing disruption, a piece of new malware is designed to steal registration keys, passwords and data from players of computer games," said Graham Cluley, senior technology consultant at Sophos.

"It's sad to think that people will be so desperate to do better in a virtual world that they're actually prepared to commit a real crime.

"We expect to see more internet skirmishes between rival online gamers and malicious code to assist this kind of internet robbery in the future."

Lineage is based on a series of comic books by Shin Il-sook about a prince who tries to reclaim his rightful throne. It is part of a growing number of online games, the first of which was EverQuest.

The game hit the headlines recently when a woman was arrested in Japan for deleting her ex-boyfriend's character.

The couple met online in the game and started a real relationship, but when it ended she hacked into his account and destroyed his virtual weapons and clothes.

More information about the LegMir-Y Trojan can be found here.