Distributed denial of service attacks, known in the security trade as DDOS, are one of the fatal hazards that all online businesses face. But data centre managers who put their faith in users of cloud computing, could be sleepwalking into a poisonous smog from which they'll be lucky to merge alive.

Data centre guru Dominic Monkhouse, MD of hosting company Peer1, described the dangers.

There are unscrupulous companies out there who want to see their rivals' budgets rapidly depleted, he explained. And there are even more unscrupulous companies who will do that for them, for a fee. The vehicle for this competitive skullduggery is cloud computing.

Cloud computing means you pay for resources as you use them. But what if a rival found a way of making you waste all your budget on resources you don't need? Under many existing cloud computing contracts, a client will automatically be given more resources whenver it looks like their server or ther bandwidth is being flooded. Such is the arrangement, they will automatically be billed too.

All it takes to empty your entire budget, then, is for a massive DDOS attack on the site, which forces your company to order masses more bandwidth and computing resources.

'It's a classic way for an unscrupulous company to take out a rival,' said Monkhouse, 'and it's possible because some service providers never monitor usage.'

'The flexibility of cloud computing has inherent dangers,' he warned.