Summer 2004 and the first virus spread by mobile phones was sent to Anti-Virus firms. The worm, known as Cabir, could have infected phones running the Symbian operating system. No infections were reported, but this was one of the first signs that Mobile Phone viruses were indeed possible.

When the infected file is launched the mobile phone's screen displays the word "Caribe". Not the most devastating virus in the world. So how does it spread? When the infected phone is turned on, the worm launches itself and scans via bluetooth for other phones to infect, sending a copy of itself to any it finds. Any phone user in the vicinity with bluetooth enabled and with a compatible device would have to accept the virus which would be preceded by a warning that the source of the file is unknown.

A few months later users who had installed a pirated game called Mosquitos on their mobiles found the game sending SMS messages. The original game was programmed to send these SMS messages as an anti piracy feature. So although this was an unintended 'Trojan' it shows what could be possible. If it was sending to a premium rate number as was first reported (but was not the case) it could have cost the user a lot of money.

There is a second kind of virus that can effect mobile phones even though it isn't spread by them. It take the more traditional route of an e-mail computer virus and connects to an SMS gateway (an internet service which can trigger the sending of and SMS) sending messages to random mobile phone numbers. 'Timofonica' was one such virus effecting customers of the Spanish phone company Movistar.

So should we be worried? I don't think there is any immediate cause for alarm, but with phones becoming more and more sophisticated there are bound to be security flaws which hackers, crackers, and virus writers will look to exploit. Phones are now massively connected so there are plenty of channels for any virus writers to use.