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Definition: A virus is a software program, script, or macro that has been designed to infect, destroy, modify, or cause other problems with a computer or software program. Users can protect themselves by installing an anti-virus protection program.

History: A software program first written by Fred Cohen in 1983, and later coined in a 1984 research paper.

Find information about the latest virus threats and updates at Symantec Security Response

Also see: anti-virus, Boot sector virus, CMOS virus, Companion virus, Executable virus, Hoax, Intruder, Logic bomb, Macro virus, MBR virus, Multipart virus, Non resident virus, Overwrite virus, Polymorphic virus, Resident virus, Stealth virus, Trojan horse, Vaccine, Security definitions, Worm, Zoo


History: First developed by two researchers at Xerox PARC in 1978, a worm is a destructive software program containing code capable of gaining access to computers or networks.

Method: Once within the computer or network, it causes that computer or network harm by deleting, modifying, distributing, or otherwise manipulating the data.

Also see: Security definitions, Trojan Horse, Virus