Vaccination

A technique of some anti-virus programs to store information about files in order to notify the user about file changes. Internal vaccines store the information within the file itself, while external vaccines use another file to verify the original for possible changes.

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.

VBS

Visual Basic Script. Visual Basic Script is a programming language that can invoke any system function--including starting, using and shutting down other applications without--user knowledge. VBS programs can be embedded in HTML files and provide active content via the Internet. Since not all content is benign, users should be careful about changing security settings without understanding the implications. This file type has the extension VBS.

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.

Some viruses display symptoms, and some viruses damage files and computer systems, but neither symptoms nor damage is essential in the definition of a virus; a non-damaging virus is still a virus.

There are computer viruses written for several operating systems including DOS, Windows, Amiga, Macintosh, Atari, and UNIX, and others. McAfee.com presently detects more than 57,000 viruses, Trojans, and other malicious software. (Note: The preferred plural is the English form: viruses)

See Also: Boot Sector Infector, File Viruses, Macro virus, Companion Virus, Worm,

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.

Most hoaxes contain one or more of the following characteristics:

• Warnings about alleged new viruses and its damaging consequences,
• Demands the reader forward the warning to as many people as possible,
• Pseudo-technical "information" describing the virus,
• Bogus comments from officials: FBI, software companies, news agencies, etc.

If you receive an e-mail message about a virus, check with a reputable source to ensure the warning is real. Visit McAfee.com’s Virus Hoax page (http://vil.mcafee.com/hoax.asp) to learn about hoaxes and the damage they cause. Sometimes hoaxes start out as viruses and some viruses start as hoaxes, so both viruses and virus hoaxes should be considered a threat.