Computer VirusComputer Virus

A A computer viruscomputer virus is a is a computer programcomputer program that can copy that can copy

itself and infect a computer. itself and infect a computer.

MalwareMalware

short for short for malicious softwaremalicious software, is , is softwaresoftware designed to infiltrate a designed to infiltrate a computer without the owner's computer without the owner's

informed consentinformed consent..

AdwareAdware or or advertising-supported advertising-supported softwaresoftware

is any is any softwaresoftware package which package which automatically plays, displays, or automatically plays, displays, or downloads advertisements to a downloads advertisements to a computer after the software is computer after the software is

installed on it or while the application installed on it or while the application is being used. Some types of adware is being used. Some types of adware

are also are also spywarespyware and can be and can be classified as classified as

privacy-invasive softwareprivacy-invasive software..

SpywareSpyware

SpywareSpyware is a type of is a type of malwaremalware that is that is installed on installed on computerscomputers and that and that collects information about users collects information about users

without their knowledgewithout their knowledge

Antivirus (or Antivirus (or anti-virusanti-virus))

Antivirus (or Antivirus (or anti-virusanti-virus) ) softwaresoftware is is used to prevent, detect, and remove used to prevent, detect, and remove malwaremalware, including , including computer virusescomputer viruses, ,

wormsworms, and , and trojantrojan horses horses. Such . Such programs may also prevent and programs may also prevent and

remove remove adwareadware, , spywarespyware, and other , and other forms of malware.forms of malware.

Computer WormComputer Worm

A A computer wormcomputer worm is a self-replicating is a self-replicating computer programcomputer program. It uses a network . It uses a network to send copies of itself to other nodes to send copies of itself to other nodes

(computers on the network) and it (computers on the network) and it may do so without any user may do so without any user

intervention.intervention.

Trojan HorseTrojan Horse

The The Trojan HorseTrojan Horse was a tale from the was a tale from the Trojan WarTrojan War, as told in , as told in VirgilVirgil's 's LatinLatin

epic poemepic poem The The AeneidAeneid. .

Note:Note:

A true virus can only spread from one A true virus can only spread from one computer to another (in some form of computer to another (in some form of

executable executable codecode) when its host is taken to ) when its host is taken to the target computer; for instance because the target computer; for instance because

a user sent it over a network or the a user sent it over a network or the Internet, or carried it on a removable Internet, or carried it on a removable

medium such as a floppy disk, CD, DVD, or medium such as a floppy disk, CD, DVD, or USB drive. Viruses can increase their USB drive. Viruses can increase their

chances of spreading to other computers chances of spreading to other computers by infecting files on a network file system by infecting files on a network file system

or a file system that is accessed by or a file system that is accessed by another computer.another computer.