It’s the season to be jolly unless you’ve clicked on a new Santa Claus worm that’s spreading across AOL, MSN and Yahoo instant messengers.

According to security firms, the M.GiftCom.All worm targets buddies in existing buddy lists to send across a link to a website claiming it be a Santa site. While many users tend to ignore spam messages or random links send from random bots, the validity of the M.GiftCom.All worm goes up significantly, since many assume that the link is coming from one of their buddies, which is not the case.

Once the user clicks on the link, it takes you to a Santa site, which then downloads malicious code to gather confidential information. Security experts say the malicious code usually surpasses firewall and other security software due to the validity of its name, "Gift.com". Once downloaded, it attempts to disable all security applications and adds a key logger to collect confidential information. M.GiftCom.All redistributes itself by targeting the infector’s AOL, MSN and Yahoo IM buddy lists.

IMlogic, a firm focused on IM security, labels M.GiftCom.All as a "Medium" threat worm, which comes as a surprise to many. Majority of the IM worms are categorized under "Low" classification in IMlogic’s database.

As always, security experts suggest that users do not click on links unless they have verified it with the sender.