Security experts report a new variant of the Skype worm which recently appeared has made the jump to other instant messengers:
"They're using Skype as a jump off into other more established networks," Boyd said. "The infection will go looking for other instant messaging clients that are on the PC and then attempt to send the infection message that it initially sends through Skype through these other chat systems."
For a computer to be infected, a user must first click on a link and then agree to download an executable file. In one sample provided by Boyd, the malicious link is listed below the instant message, "Check this out. Give me your opinion."
Once installed, the worm will gradually start to send out messages to the victim's contacts, Boyd said.