Instant messaging security threats are growing by 50 per cent each month and could potentially spread across the globe in seconds.

According to research from anti-virus firm F-Secure, virus writers are targeting instant messaging application due to their ability to spread malicious code faster than email worms.

Where as the Sasser email worm took 14 minutes to compromise 95 per cent of all vulnerable PCs around the world, instant messaging worms could infect all IM using computers in just 14 seconds.

The anti-virus firm claims to have detected 200 instant messaging worms, plus more than 700 trojans, backdoors and password stealers that target the application.

'IM worms don't waste time scanning machines that are not infectable they only target other IM using machines,' said Patrick Runald, technical manager at F-Secure.

With analyst firm IDC predicting that 506 million people will use instant messaging by 2008, this could present new security concerns for IT departments.

'As IM grows and comes into corporations it could become more of a risk,' said Runald.

Mikko Hypponen, F-Secure's director of anti-virus research, told Computing that more than 50 per cent of last year's largest viruses were designed by criminals to make money and that mobile viruses could become a greater focus for organised crime outfits.

'PCs don't have in-built billings systems but mobile phones do,' said Hypponen. 'Mobile malware can be designed to infect phones and message premium rate toll numbers. You'll only find out about it when you get your next phone bill.'

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