Do not open unexpected attachments. It was first identified in Europe on Thursday, where it had been spreading slowly. Even though the virus does not carry a destructive payload, it can crash email servers if it gathers enough steam. McAfee said the virus seems to have increased its rate of spread in recent days, although the malicious program actually contains a bug that allows a user to make it inactive. Users receive Navidad via e-mail in the form of an attachment with the name navidad.exe.
Users receive the attachment as a reply message to an e-mail sent to an infected user.
Once the virus has infected a PC, it prevents users from launching any programs of the .exe type, which includes basic applications such as Microsoft Word. Navidad is the Spanish word for Christma s. The latest hole involves Microsoft Outlook and Outlook Express e-mail clients. The latest vulnerability impacts all users of Outlook Express and a very wide swath of Outlook users, Microsoft said. However, it is even more destructive than Melissa in that it deletes necessary system files as well as data files.