A new computer virus named Melissa continued to infect electronic-mail systems worldwide yesterday, shutting down some companies' e-mail networks and raising concerns about future damage.

Locally, Bethesda aerospace and defense company Lockheed Martin Corp. had to shut its 110,000 e-mail users off from outside networks after Melissa paid a visit Friday afternoon.

As of yesterday, the company was preventing all outside e-mail transmissions except for critical communications with the government and other customers.

Giving up virtually all e-mail is no small sacrifice for Lockheed Martin, which churns out more than 30 million messages in a typical month.

"It's still causing some problems for us," Elaine Hinsdale, a spokeswoman for Lockheed Martin's enterprise information systems division in Orlando, Fla., said of the virus.

Other organizations affected include the chemical company DuPont Co. in Wilmington, Del.; electronics maker Honeywell Inc. in Minneapolis; the North Dakota state government; and Compaq Computer Corp. in Houston.

According to Carnegie Mellon University's Computer Emergency Response Team (CERT), a computer-security organization that is tracking Melissa, the virus was first reported Friday morning.

CERT estimated that the virus has caused more than 100,000 personal computers to send out dozens of infected e-mail messages.

That estimate was based only on first-hand reports, prompting a team leader, Jeff Carpenter, to suggest that the actual infection rate was much higher.

"We believe this is only the tip of the iceberg," Carpenter said from his office at the Pittsburgh-based university.

Melissa infects computers that have Microsoft Word 97 or Word 2000 programs installed, and any e-mail system that comes into contact with the virus could be harmed.

So far, it appears that Melissa can be spread only by a computer user opening an e-mail message containing an infected Word document as an attachment.

Overloads system

Once the document is opened, the virus may propagate by sending an e-mail to the first 50 entries in the user's electronic address list.

This can overload e-mail systems and cause the spread of sensitive information.

CERT reported that Melissa commonly introduces itself in a system as an "important message" from someone known to the computer user.

When the document is opened, it commonly reads, "Here is that document you asked for don't show anyone else ;-) [a wink and smile formed by punctuation marks]". The document may also contain lists of pornographic Web sites.

Besides Lockheed Martin, Maryland businesses and government agencies reported little or no trouble with Melissa yesterday, though several had issued warnings to employees about opening "important messages."

"We have had no reported problems with this virus," said Barbara Lucas, a spokeswoman for Black & Decker Corp. in Towson.

Many area businesses declined to discuss whether they had been touched by Melissa, citing security concerns.

The Associated Press contributed to this article.

Pub Date: 3/30/99