As mobile phones become more complex, and more like portable computers, how much at risk are they from their own breed of virus? Spencer Kelly has been finding out how big the threat really is.
On the surface, conditions seem perfect for a smartphone virus outbreak.
Could smartphones become as vulnerable to malware as PCs?
First, anyone can write programs for them. There are now hundreds of downloadable games and utilities, and most are written by third party vendors.
Secondly, smartphones are well connected. With Bluetooth, infrared, text and picture messaging, they can pass on data, or malicious software, to any other phone in the world.
There is certainly plenty of scope for malicious smartphone software to be written, and spread, very quickly through the mobile world.
So where is the mobile virus outbreak the doom-mongers have been predicting?
Sal Viveros, of McAfee, says: "Right now we don't see mobile viruses as a big threat.
"It's a growing threat, and something we'll see in the future, but currently, the ones we see now haven't spread very far.
"The main reason is that we haven't seen a critical mass of the smartphone devices for these things to travel to."
That is not to say there is not any malicious mobile software out there.
Mostly written as proofs of concept, several pieces of malware with suitably scary names have hit the headlines recently.
Skulls is targetted at the Symbian Series 60 operating system
We managed to track down a few for the Symbian Series 60 operating system, which runs on Nokia smartphones.
One of these was Skulls, which some users have mistakenly downloaded and installed from an otherwise normal looking website.
Douglas Overton, of Wireless Data Services Global, says: "Once it's on your device it will slowly disable the functionality of your main applications - contacts, calendar, e-mail - and at the same time replace all of the icons on the desktop of the phone with a skull."
Commwarrior is a more virulent type of attack, which spreads from one phone to another via Bluetooth and MMS (multimedia messaging service).
Douglas Overton explains: "Commwarrior is operating in the background. It will target various people in your contacts, select a mobile number at random and then send them an unsolicited message."
But still, viruses and worms have not terrorised the smartphone world like they have the PC world.
Our handsets are not melting in our hands, the skies have not fallen. Why?
Malware will not infect your phone unless you accept it
Perhaps the biggest barrier to a mobile virus outbreak is the OK button.
Unlike in the PC world, no application that tries to enter your phone can come in without permission from the user.
If your phone was a house, all incoming programs would have to ring the bell, and wait for you to let them in.
Douglas Overton says: "Any application that you install on a Symbian or a pocket PC device will prompt you through a series of dialogue boxes that will pop up on the screen, saying 'Do you wish to install this - Yes or No?'
"So unless you have explicitly downloaded that file and you know what it is, or somebody's transferred it to you, my advice would be to reject it."
In case a piece of malware does con its way in through the front door, there are now ways to check if something bad has got in.
Just like a burglar alarm can monitor your house, mobile-specific antivirus software can search and destroy any nasties on your phone.
And the manufacturers are also planning to add more internal protection, according to Symbian's David Wood.
"We're going to put something in place which can be likened to protection on individual rooms.
"In the same way that your gardener may be allowed in your conservatory but he has no business in your bedroom, so some applications may have access to the telephony but not to your contacts database."
Safe or stifled?
But prevention is better than cure. If it wanted to, the mobile phone industry could kill any future virus problem before it happened.
Manufacturers could lock down the sensitive parts of the operating system: the parts that control making phone calls, sending texts, spending the user's money.
By doing that, even if a virus got into your phone, it would not be able to send itself to other phones.
This may seem an obvious solution. But as David Wood says: "There's a very important balance you've got to strike here.
"It is important to allow new applications to have access to telephony and other aspects of the billing system because they're going to do things which end-users are going to find very useful."
Douglas Overton adds: "One of the problems of locking down the operating system is that you will stifle innovation in the software development community.
"Many of the more innovative programs or games will make use of the radio functions of the device - for instance, multi-player gaming, location-based service applications."
Mobile viruses currently are very rare (so rare we found it really difficult to actually find any to film for this programme).
But, without a doubt, as smartphones become more common, the threat will grow.
The question is: can the mobile industry learn from the PC industry's mistakes?
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