What Are Viruses, Worms And Trojans

What are Viruses, Worms and Trojans?

A computer Virus, according to Webster's Collegiate Dictionary, 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)". Two categories of viruses, macro viruses and worms, are especially common today.

A Macro Virus is a virus that exists as a macro attached to a data file. In most respects, macro viruses are like all other viruses. The main difference is that they are attached to data files (i.e., documents) rather than executable programs. Many people do not think that viruses can reside on simple document files, but any application which supports document-bound macros that automatically execute is a potential haven for macro viruses.

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 difference is that unlike viruses, worms exist as separate entities; they do not attach themselves to other files or programs. Because of their similarity to viruses, worms are often also referred to as viruses. A well-known example of a worm is the ILOVEYOU worm, which invaded millions of computers through email in 2000.

Named after the wooden horse the Greeks used to infiltrate Troy, a Trojan horse is a program that does something undocumented which the programmer intended, but that the user would not approve of if he or she knew about it. According to some people, a virus is a particular case of a Trojan horse, namely one which is able to spread to other programs (i.e., it turns them into Trojans too). According to others, a virus that does not do any deliberate damage (other than merely replicating) is not a Trojan. Finally, despite the definitions, many people use the term "Trojan" to refer only to a non-replicating malicious program. An example of a Trojan horse is W32.DIDer. This virus has been found on the computers of users who have downloaded the popular file-sharing program Grokster.

What are Hackers/Crackers?

The popular definition of hacker describes a person who maliciously gains unauthorised access to computer systems with the intent to snoop, steal or corrupt data.

What do you need to do to protect your computer from these problems?

The minimum you require is :-

1. A Virus protection system to block, detect and remove viruses.

2. A Firewall which protects your PC from Hackers, Trojans,