BleepingComputer.com: New Im Attacks, Bugs Signal Stealthier Exploits

...newly found IM vulnerabilities indicate how lethal an IM attack could be: The AIM bug doesn't even require that the victim take any action at all to become infected.

And there are signs that the bad guys are gradually starting to use IM's rapid-fire transfer of messages as a more efficient way to spread bot infections, send spam, or conduct targeted attacks than store-and-forward email... there was a 20 percent increase in these attacks versus the same period last year...