'Tis the Season
Maldal is the name of the latest virus. Though Maldal, like Goner, is relatively unsophisticated, it has the potential to deliver a very destructive payload.
Since the attachment is called "Christmas.exe" and the e-mail may look like it was sent from a familiar address, many users will no doubt unwittingly infect their computers. Once clicked, the virus will attack anti-virus and firewall software, delete operating system files, send itself to everyone in the contact list, and display a graphic of Santa Clause. Cute.
So, update your anti-virus software, and--for heaven's sake--don't click on any suspicious attachments, even if they are from someone you know--especially if they end in ".exe". If you do receive an attachment that you weren't expecting from someone you know, send them an e-mail to inquire about the validity of that attachment.