“Security update #12: Significant security update.”

If you’ve received an MMS like this from one of your friends, you’d better think twice before approving the installation on your phone – chances are you’ve been sent a mobile virus nicknamed Commwarrior which spreads via MMS messages over Bluetooth.

A mobile virus is similar to an e-mail virus except it targets mobile phones or wireless-enabled PDAs. A BBC report dating back to January 2003 had highlighted the potential threat of mobile viruses, so they’ve actually been around for some time.

Less contagious but still a nuisance
I guess the reason they’ve not been as virulent as their e-mail cousins is that not that many people have Bluetooth-enabled phones and those that do don’t always turn their Bluetooth on. The fact that Bluetooth only works within 10 metres is also a natural barrier against mass infection.

The Cabir virus was the original mobile virus. It was created as a proof-of-concept virus by a bunch of computer scientists who sent it to anti-virus firms. This harmless concept has morphed into much more malicious versions now found in more than 20 countries, including the US, Japan, Finland, South Africa and Singapore.

If the infected file is launched, the phone screen will display the inscription “Caribe”. The worm penetrates the system, scans accessible phones via Bluetooth and sends a copy of itself to the first one found. Cabir will drain the power from your phone as it replicates itself.

The biggest outbreak of Cabir took place in Nokia-land itself, Finland (I guess everyone there has Bluetooth phones). Crowds gathering at Helsinki’s Olympic Stadium for events sponsored by the International Association of Athletics Federations this past August experienced virus infections over a very short period of time.

Another famous mobile virus is called Mquito and it’s derived from a cracked version of a mobile phone game called Mosquito. It’s categorised as a Trojan virus as it disguises itself as a useful program while secretly performing other undesired functions.

This nasty bug was spawned from an anti-piracy plan that backfired. The pioneering version of the Mosquito game was engineered to secretly send an SMS message to alert its creator if an unlicensed version of the game was being used. When this copy-protecting technique was found to have been cracked, its creators removed the program from the game.

However, pirated versions of the game on file-sharing networks still contain the virus. It is said to trigger SMS messages without user consent to a premium-rate number and users are unsuspectingly charged 1.5 pounds sterling each time the game is started.

How to avoid infection
So, how do you stop these viruses from infecting your beloved phone? Well, as they say, prevention is better than cure.

First and foremost, turn off your Bluetooth when you don’t need it. Leaving it turned on is like leaving your front door unlocked –you’ll be exposing your phone to potential attacks.

Usually, your phone will prompt you to approve or deny the installation. Of course, you can and should say “No” but a persistent attack can cause the prompt to appear so many times that you might be tempted to click “Yes” just to make it go away.

Never do that. Just walk away. Remember, I told you that Bluetooth only works within a 10 meter radius? Well, unless your attacker is tailing you – highly unlikely as most viruses are spread without the carrier knowing it – this will stop the prompts from appearing.

Also, don’t download pirated mobile games from file-sharing networks. I’m not being a moralist here. I just want to save your phone from being infected. Although pirated games are not all carrying viruses, you are treading on dangerous ground when you download something from a pirate source.

There are anti-virus programs for mobile phones available from the likes of Symantec and F-Secure. But these do cost money. Just take my advice and your phone will stay healthy and virus free!