Variant A modified version of a virus. Usually produced on purpose by the virus author or another person amending the virus code. If changes to the original are small, most anti-virus products will also detect variants. However, if the changes are large, the variant may go undetected by anti-virus software. Virus A computer program file capable of attaching to disks or other files and replicating itself repeatedly, typically without user knowledge or permission.
Some viruses attach to files so when the infected file executes, the virus also executes.
Other viruses sit in a computer's memory and infect files as the computer opens, modifies or creates the files. There are computer viruses written for several operating systems including DOS, Windows, Amiga, Macintosh, Atari, and UNIX, and others. Virus Hoaxes Hoaxes are not viruses, but are usually deliberate or unintentional e-messages warning people about a virus or other malicious software program. Some hoaxes cause as much trouble as viruses by causing massive amounts of unnecessary e-mail. If you receive an e-mail message about a virus, check with a reputable source to ensure the warning is real.