Computer hackers cost European businesses $4.3bn in lost revenue last year, according to recent research.

A study of 3000 businesses worldwide found that lapses in security cost companies between 5.7 and 7 per cent of their annual revenue, or six cents for every dollar in sales.

Frank Bernhard, managing principal of Omni Consulting Group, which carried out the study, said online security problems are growing faster than anyone could imagine. "That whole issue could explode," he said, adding that when hackers break into company source code, "you're into billions of dollars that just walked out the door."

Bernhard believes that companies need to consider their intellectual property assets and cited Microsoft's recent denial-of-service attacks, which crippled most of its major web properties, as an example.

"The answer is clear: [Microsoft] did not have a corporate policy body looking at security [and] now it does," he said.

Bernhard believes that although European companies are less stringent about introducing security policies and are more relaxed about intrusion threats, they are beginning to recognise the implications of hack attacks and the need for protection. "European organisations are more adapt and inclined to scale up towards network security," he said.

He stressed that companies need to put security measures in place and implement policies to protect their intellectual properties. He gave the example of someone walking into an office building and stealing a photocopier. "How can you miss someone walking out with the equipment and how can you miss someone walking away with your source code?"

The study found that non-IT organisations and manufacturing companies were best at protecting their intellectual properties. "The ones that we'd think have the security tools are the weakest link in the puzzle," he said.