THE first computer worm designed to spread between cellphones was demonstrated last week. And though it was dismissed by phone makers as a harmless prank, experts say it is only a matter of time before a truly destructive specimen arrives.

The virus, called Cabir, was unleashed by an underground virus authoring group calling itself 29a. The worm spreads between phones running Nokia's Series 60 smartphone software, which runs on the Symbian operating system.

Cabir does not spread via the cellphone network in the way that a computer virus would exploit the internet. Instead, it uses the Bluetooth short-range radio communications protocol to infect devices up to a few tens of metres away. Safeguards built into Bluetooth mean a user has to confirm that they wish to receive the message carrying Cabir - which, ironically is disguised as a phone security application - for their phone to become infected.

Phone makers ...