Next year will see an upsurge in voice over IP (VoIP) hacking attacks as more businesses implement the technology, security experts predict.

As increasing numbers of companies and consumers switch to internet telephony, cyber criminals will exploit vulnerabilities in the application and launch attacks, according to Paul Wood, senior analyst at MessageLabs.

He claims that malicious users could unleash a telephone call that causes the application to crash, infects the computer and renders control to the attacker.

"We can probably expect to see early forms of VoIP attacks in the new year," warned Wood. "With the increasing adoption of Google Talk, Skype and other internet telephony applications, the system will become a rich target for spammers and malware writers. Similarly, as Instant Messenger (IM) becomes more prevalent, it creates a fertile environment in which criminals can operate."

MessageLabs latest annual intelligence report, released this week, predicts that IM threats will become more aggressive in 2007. Moreover, it warns that social networking sites, such as MySpace and Facebook, will become increasingly attractive targets for hackers due to the accessible information that is posted, making it easier for them to launch targeted attacks.

The report also found that the average spam level this year jumped to 86 per cent, driven by an increase in sophistication of botnets and targeted techniques. Experts predict that spam will become even more specific next year. Furthermore, the hackers will continue to pursue industry sectors with the use of geek spam to enhance the chances of success. The financial and legal professions appear to be the criminal's next target.

"2006 was the year that spammers took the security industry by storm and showcased their new tactics and techniques for mass disruption," said Mark Sunner, chief technology officer at MessageLabs. "Spam has categorically shed its title of being a nuisance and is a perilous threat, which all companies need to be protected against. Next year will certainly bring more targeted and sophisticated attacks as the bad guys continue to sharpen their tools."

Security professionals also envisage the convergence of threats such as spam, viruses and spyware, as email security becomes tighter. They warn that the criminals will send more malicious emails with URL links to avoid detection in security filters.