A Trojan horse that made the rounds last month is at it again according to recent reports, and this time it seems that the virus is propagating via instant messaging clients like AOL instant messenger, Yahoo Chat and Google Chat. "It injects a message and URL only into already-open windows," said Alfred Huger, senior director of Symantec's security response team. "It's not just some random message that pops up, but it appears only to people [you are] already talking to. That makes the approach very effective." And just what might that message be? I just have to quote ComputerWorld here because there's no way I could possibly do this sentence justice: "An alert to some Symantec customers pegged the new infection vector as 'insidious' because the message--such as the cryptic 'LOL ;)'--and the included URL can be dynamically updated by the attacker." All joking aside, make sure that your users are aware of the threat and ensure that all your virus definitions are up to date...LOL.

For more info on the Trojan threat:
- see this ComputerWorld article