Trojan horses: A Trojan horse is a program that does something undocumented which the programmer intended, but that users would not accept if they knew about it.

Because of their similarity to viruses, worms also are often referred to as viruses. Unlike viruses, however, worms exist as separate entities they do not attach themselves to other files or programs.

Worms: Worms are very similar to viruses in that they are computer programs that replicate functional copies of themselves (usually to other computer systems via network connections) and often, but not always, contain some functionality that will interfere with the normal use of a computer or a program.

The main difference is that they are attached to data files (that is, documents) rather than executable programs.ĭocument-based viruses are, and will likely continue to be, more prevalent than any other type of virus. In most respects, macro viruses are like all other viruses. A macro virus is thus a virus that exists as a macro attached to a data file.

Macro viruses: A macro is a piece of code that can be embedded in a data file.

Once created and released, however, their spread is not directly under human control.

Computer viruses are never naturally occurring they are always man-made.

Resources and more information about virusesĭefinitions of viruses, worms, and Trojan horsesĪccording to Webster's Collegiate Dictionary, a computer virus is 'a computer program usually hidden within another seemingly innocuous program that produces copies of itself and inserts them into other programs or files, and that usually performs a malicious action (such as destroying data)'.

Definitions of viruses, worms, and Trojan horses.

How does worm virus work