Experts: 'Melissa' capable of espionage

The 'Melissa' macro virus that forwards files to other e-mail addresses may be passing more than a Word file with porn sites listed inside. Virus experts say it could be surreptitiously e-mailing confidential information, too.

"We have had several calls from industry lawyers and government representatives that are worried that this could happen," said Jeff Carpenter, team leader for the Centre for Emergency Reponse Teams (CERT) at Carnegie Mellon University.

How could 'Melissa' purloin classified documents?

The virus infects the default Word template -- called normal.dot. Every new document created on an infected PC carries the virus.

So imagine creating a confidential document -- say, SECRETPLANS.DOC. If it's created on an infected system, the file would, upon sending it to a trusted colleague, find itself being passed on to the top 50 entries in your colleague's address book, as per the scripted instructions of the Melissa Word macro. "The possibility of passing along confidential information is a scary new twist," Carpenter said.

This new wrinkle may have served as the impetus by federal law enforcement officials to send out on Sunday their first-ever warning about a computer virus.

The Federal Bureau of Investigation joined with the infant National Infrastructure Protection Centre to issue a warning in an attempt to stem the tidal wave of email that is expected to hit the virtual shores of corporations, government, and military servers on Monday.