The virus, W97M_Melissa, uses a combination of Microsoft Word macros and Microsoft Outlook to send a list of 80 pornographic Web sites. It works with either Word 97 or Word 2000, according to antivirus companies TrendMicro, Symantec, and Network Associates.
The program is somewhat devious in that it sends itself from the email addresses of people who are likely to be familiar contacts, arriving as email with the subject line "Important message from..." followed by the sender's name. The body says "Here is that document you asked for...don't show anyone else ;-)." The email includes an attached Word file "list.doc," which includes the porn sites' addresses.
The virus doesn't appear to cause any damage to infected computers except in rare cases when the minutes of the current time match the date--for example at 4:26 p.m. on March 26. In this instance, the virus will insert the Bart Simpson quotation, "Twenty-two points, plus triple-word-score, plus fifty points for using all my letters. Game's over. I'm outta here," into a user's active document.
Because the virus sends itself to potentially thousands of contacts contained in a user's address distribution list, however, there's a possibility that the virus could overwhelm mail servers.
"We've been swamped all day with customers calling in with this," said Dan Schrader, director of product marketing at TrendMicro. "It's spreading extremely quickly. Twenty major corporate sites have called us."
The virus first was spotted today, according to TrendMicro and others.
It is similar to an "autospam" virus called "Share Fun" that emerged in March 1997, Schrader said, but that virus was buggy and not as effective. There have been viruses that spread through the address books in the past, "but never this effectively," Schrader said.
Network Associates estimated the virus has already hit hundreds of thousands of computers.
Twenty of the company's largest clients were infected; one firm alone said it had reached 60,000 computers. "The propagation rate has been alarming," a company spokesperson said.
Tom Moske, a network administrator at USWeb/CKS, ran into the virus this afternoon when the virus spread itself from people in his company who had opened the attachment.
And he had cause to appreciate the devious nature of the virus, since it spread from employees in his company spread it to the business clients of USWeb/CKS.
"It's the most intrusive I've ever seen," he said. "This is worldwide spam."
TrendMicro said the virus can be detected using its free Web-based "house call" service.
Because the virus spreads itself automatically, it could be termed a "worm." The author apparently appreciated this, remarking in the virus code: "Worm? Macro Virus? Word 97 Virus? Word 2000 Virus? You Decide!"