Computer Virus and Crime and How to Prevent It

1. What is a Virus?

A virus is a program designed to replicate itself in order to spread itself from one system to another.

Some viruses are harmless. They display only a simple message. But most viruses are very harmful. They destroy data or even the entire hard disk. Viruses attach themselves to program-files and move with them from disk to disk. When a virus attaches itself to a file, it lies dormant.

But when a certain date or event occurs, it gets triggered and becomes active. One notorious virus is called Friday, the 13 Virus. It is also called Jerusalem Virus because it was first of all discovered at the University of Jerusalem in 1987. It gets activated every Friday that occurs on the 13th of a month.

2. What does a Virus do?

What harm can a virus do when it gets active? It depends on the virus itself. It may:

1. reformat hard disks erasing them totally.
2. delete or damage files.
3. heavily damage the file-allocation table. As a result of which, files cannot be easily located and found.  Moreover, the hard disks are rendered absolutely useless.

The first documented virus-program was written in 1983 by Fred Cohen, Within only six years, i.e., by the close of the 1980s, virus had become an alarming epidemic. However, viruses need caution on the user's part. But they are not at all to be feared from. Some simple steps can protect a system from them. These steps are:

1. backing up important files frequently.
2. Write-protecting program disks.
3. Some viruses are copied from an infected disk during start-up. So, all disks should be removed from their drives before starting the computer.
4. All files that come from an unknown source should be checked with an anti-virus program. They should be used only when they are found to be totally virus-free.
5. Every PC should be equipped with some anti-virus program. Examples of such anti-virus programmers include Norton Anti-virus, Dr.Solomon's Anti-virus, McAfee Virus Scan and many others.

New viruses are being discovered every day. So, the users should keep updating their list of viruses. Also, they should take necessary precautions and steps for keeping the viruses at arm's length.

3. Types of Virus:

The different types of viruses are listed below:

a. Worm.

Originally, it is quite a harmless virus that simply replicates itself. But in the long run, it takes over all the resources of the itself. But in the long run, it takes over all the resources of the system and the PC become useless. Worms have the capacity to travel from system to system very easily.

b. Trojan Horse.

This virus comes as a friendly program (as a game etc.). But it is very dangerous as it destroys all data.

c. File Infector.

This is the most common type of virus, It adds virus code to the regular programming code within program-files. So, when the infected program is run, other program-files also get infected. 

d. Boot-Sector Virus. 

The virus attaches itself to the boot-sector of the disk. This sector is the part of the disk where start-up instructions and the file-allocation table are kept. This sector is read and loaded into the memory every time the disk is booted. Evidently, this virus is also very dangerous.

4. Computer Crime:

Computer crime means unauthorized access to or alteration in computer programs or data.

As the human society is becoming more and more dependent on computers, computer crime is talking an alarming shape. Computer criminals have done the following harms:

• They have stolen huge amounts of funds belonging to various computer companies by transferring them out of their computer accounts illegally.
• They have spread destruction from one computer to another using virus programs. Thus they have crippled the entire system of computer networks.
• They have spread computer-worm programs that are less harmful in the beginning but render the computer almost useless in the long run.

5. How to prevent Computer Crime?

The basic ways of prevention are listed below:

a. Vaccines:

These are programs that vaccinate the computers against the viruses.

b. Passwords:

Most computer systems require the user to enter a password that is usually a combination of alphanumeric characters (A-Z and 0-9). If the password is valid, the computer grants access to the system. If it is not valid, access is denied. Some complex computer security-systems trigger an alarm if someone tries to use a fake password. The longer the password, the safer it is.

c. Halting Trespassers:

In order to restrict illegal access to a computer, some sophisticated defenses are used instead of simple passwords. For example, special voice-recorders can analyses the voice of a trespasser and check it against a database containing the voice-patterns of valid users.