Intruders can get into unprotected computers and install software that allows them to remotely control the machines to do specific tasks like sending spam.

No, I don't mean 80 nodes, but 80 networks with thousands of unprotected computers.

Then he recalled the reports he had heard about the risks of exposing unprotected Windows-based computers to the Internet and how quickly they could become infected.

Maybe he knew some way to call long distance into Hannover-perhaps from some unprotected computer, or with a stolen credit card.

Hess found his way into an unprotected computer belonging to a German subsidiary of the U.S. defense contractor, Mitre.

One theory is that the program is an attempt to create software engines for sending spam by using unprotected computers that have been surreptitiously commandeered by the virus.

That is because the spammers find ways to hijack unprotected computers to relay their messages, thus hiding their true origins.

Spammers can make their messages appear to come from these unprotected computers, often without their owners being aware their machines have been tapped.

When they find unprotected computers, they try to install hidden software - called malware - that allows them to control the computers remotely.

In theory, the intruders could use the stolen information to gain access to government, educational, commercial and private files on unprotected computers connected to the Internet.