Were you hit by the Melissa virus last week? We were - and the infection came from Microsoft itself.
PC Week was unwittingly sent a copy of the virus by a Microsoft UK marketing manager. The virus jammed mail servers all over the world and forced some companies to shut down their Email systems.
Melissa, technically known as W97M_Melissa, is a self-replicating macro virus that affects systems using Microsoft's Word 97 or 2000, and Outlook products. Melissa is triggered when a user opens a Word attachment, called list.doc, in an Email whose subject line is "Important Message from (name)", where "name" is the name of the original victim.
The original victim will be someone known to the user, as the virus macro uses the first 50 addresses it finds in the user's Outlook address book to propagate itself. This makes the virus more sinister, as it seems the Email is from a genuine source.
Melissa also infects the normal.dot Word template, the default template for new documents, so that any new document created could trigger another 50 Emails. However, the virus is not destructive, and has no other lasting effect on the user's system.
Melissa was followed by a variant known as Melissa.a, which sent Email with a blank subject line. Other variants soon sprang up, as the Visual Basic for Applications (VBA) code in the macro was easily accessible and easy to modify. Another variant, "Papa", infects Excel files, and another changed the subject line of the Email message to "Urgent info inside.
Disregard macro warnings."
By sending out 50 more copies of itself, Melissa has clogged corporate mail servers, including those of Microsoft, Lucent and Intel.
Patches are now available from Computer Associates, Network Associates, Sophos, Symantec and Trend Micro. Patches are also available for Sendmail, and other Email scanning tools have been modified to detect Melissa.
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