In the past two months, over 30 new IM viruses and worms have been reported by the IMlogic Threat Center, a group consisting of vendors like Symantec, Sybari, McAfee and IMlogic, as well as IM providers AOL, Microsoft and Yahoo.

The reason for the surge in activity is that virus writers are now shifting the focus of their attack to IM systems, noted IMlogic chief technology officer Jon Sakoda. He told CIO Today that many virus writers see IM as an unprotected channel that gives them access into companies and homes.

IM Propagation and Hijacking

According to IMlogic's report, 81 percent of reported incidents include IM virus or worm propagation, with approximately 10 percent hijacking file transfer capability.

Of the reported incidents over IM networks, 70 percent targeted the MSN Messenger client, the Windows Messenger client and the MSN Network.

Eighteen percent of the incidents used the Yahoo Messenger client, and 12 percent targeted AOL's client.

The three most reported infections in corporate environments were the Kelvir, Bropia and Bizex worms, the report noted.

MSN Messenger Assaults

The IMlogic report was released just as MSN Messenger has found itself under increasing attack.

A few weeks ago, a vulnerability in the client was published online, followed by a spate of security advisories. The flaw was found in a component used to display portable network graphics (PNG) files.

Although Microsoft has issued a patch for the flaw, the flaw seems to have prompted other attempts to use IM as a method of infection.

Worm War in Progress

Beyond using IM as a delivery device, it seems that virus writers are already launching multiple types of threats to try and outdo each other.

An F-Secure antivirus researcher noted in his blog that it all sounds like a "War of the Worms," similar to the tussle that occurred last year among Bagle, Netsky and MyDoom authors.

Given the competitive feeling among virus writers, and the perception of IM being an unprotected channel, it is likely that IM threats will continue with increasing frequency, IMlogic noted.

Currently, threats are growing at approximately 50 percent per month, the threat center reports.

"The data absolutely suggests that the number of threats being reported is increasing at a fairly substantial rate," said Sakoda. "Also, these types of threats are mutating, which makes them difficult to combat."