Currently there are no widespread outbreaks of malicious code circulating via instant messaging. In the past, however, some malicious code did take advantage of IM. Always use normal security precautions whenever you use IM.
How They Attack?
Malware
How You KnowIM attachments, just like email attachments, can carry destructive viruses, Trojan horses, and worms
Some new worms use IM software to send themselves...
