Mob game 'virus' was developer gaffe - security firm

Security experts have quashed reports that a pirated mobile videogame was host to the world's first malicious mobile phone virus, after it emerged that the supposed 'Trojan horse' component was originally inserted as a copy protection measure by the game's developer.

According to reports that sprang up yesterday, a pirated version of the game Mosquitos found on file-sharing networks and download sites would install a program that sent out unauthorised SMS text messages while the game was running.

Initial reports suggested that the malicious code in the game, which runs on the Symbian Series 60 operating system (used by mobile phones including the Nokia N-Gage), would send the text messages to a premium rate number - and had been added by the programmers who cracked the software.

However, according to anti-virus researcher F-Secure, the Trojan element was originally inserted by the developer in an effort to alert them to unlicensed copies. The idea was that the program would send a message alerting the developer to the use of unlicensed software. The service has since been shut down due to complaints, and text messages to the number are no longer charged at premium rates.

"It did not work the way it was supposed to; they had complaints and removed it from the game," F-Secure's Mikko Hypponen told the BBC News website. In its advisory on the subject, F-Secure said: "This functionality was intended to be a copy-protecting technique - it didn't work as planned and the whole functionality backfired."

"The premium rate contracts for the phone numbers have been terminated, so although old versions of the game still send hidden SMS messages, it only costs the nominal fee of sending the message itself. Current versions of this game no longer have this hidden functionality, but 'cracked' versions of Mosquitos still float in P2P network - and they still send these messages."

F-Secure advised mobile phone users only to download their software from authorised vendors.