zombie

a personal computer affected by a virus which causes it to send out large amounts of unwanted e-mail (spam), without the user's knowledge

Could there be a zombie lurking somewhere around your home? No, I'm not referring to a corpse revived by African witchcraft, or even an apathetic teenager who doesn't want to get out of bed! This zombie is likely to be perched innocently on a desk in your study or living room … In 2005, one of the primary uses of the word zombie is as a means of referring to a personal computer which, usually via broadband Internet exposure, has been affected by a virus causing it to generate large amounts of spam.

the increased use of high-speed broadband Internet connections and a general lack of awareness of associated security risks are thought to be the main factors underlying this most recent medium exploited by spammers

It is currently estimated that at least one third of all spam circulating the Web is being relayed through home PCs which have unwittingly become zombies. The increased use of high-speed broadband Internet connections and a general lack of awareness of associated security risks are thought to be the main factors underlying this most recent medium exploited by spammers, who compromise the PCs of innocent home and small-business users with Remote Access Trojans or RATs (a trojan or Trojan horse is a computer virus disguised as a program). The activity of rendering a personal computer a zombie is sometimes referred to by the transitive verb zombify, and a related participle adjective zombified is very common, as in zombified PCs/computers.

Background – zombie

This use of the term zombie is the latest among various uses that have been established since the advent of the World Wide Web. The original use of the word zombie in Internet contexts was as a means of referring to an abandoned or out-of-date website, sometimes alternatively referred to as a ghost site, that for some reason had been moved to another web address. The word zombie has also been used to refer to an insecure web server which is exploited with malicious intent in order to attack websites.

The word zombie is of West African origin and dates back to the late nineteenth century, when it was used to refer to a dead person revived by voodoo witchcraft. The actions of a zombie were said to be under the control of the person that had performed the ritual resurrection (hence the current analogy of gaining control of someone else's computer). By the 1940s, the word was being used with its familiar sense of a lifeless, apathetic person, the idea being that such an individual resembled a revived corpse.