Some users over the weekend may have noticed that links in Windows Live Messenger 2009 will not work. This temporarily block is to ensure that a malicious worm doesn't spread through anymore computers.
The Windows Live team posted about the security risk on their website warning users that the temporary measure is for users safety, at least until the worm properly dealt with. Windows Live Messenger 2011 is currently not affected, so users are encouraged to upgrade to the latest version of Messenger or simply wait until the worm is under control.
The malicious worm is quickly spreading through Messenger 2009, sending messages to unsuspecting users through an active link. When the victim clicks on the link, it opens in a web browser, downloading the worm onto the recipients computer. The process is repeated to the victims contacts, sending users a link to the infected website.
Windows Live Messenger 2009 users may see a warning on their contact window, alerting users of unavailable features. In case anyone believes they may be infected, it's best to keep your anti-virus software and definitions up-to-date. Users should also update to the recent Windows Live Essentials 2011 to ensure they are fully protected.
Thanks to Adnan for the news tip!