Microsoft's lawsuit against alleged zombie networks stemmed from monitoring of a single hijacked computer the company says sent out 18 million spam e-mails.

Microsoft said this week that the PC purposely infected with a malicious code drew spammers like flies, registering 5 million connections that produced 18 million e-mail messages in just 20 days.

The messages were never actually sent out since the PC was quarantined; however, Microsoft and U.S. regulators used the information to file legal action last August against more than a dozen alleged spammers.

The Seattle Post-Intelligencer said the lawsuit focuses on the alleged hijacking of the computer rather than the fraudulent nature of the spam itself, as was the strategy in past suits.

In the meantime, consumers were urged again to have spyware and a sturdy firewall installed and to stay away from unsolicited e-mail.

Copyright 2005 by United Press International