Nowadays, it can be said there are more and more threats over the Internet. Malware is a general name for all programs that are harmful; viruses, trojan, worms and all other similar programs.

A computer virus is a program, a block of executable code, which attach itself to, overwrite or otherwise replace another program in order to reproduce itself without a knowledge of a PC user. There are a couple of different types of computer viruses for example boot sector viruses, parasitic viruses, multi-partite viruses, companion viruses, link viruses and macro viruses. These classifications take into account the different ways in which the virus can infect different parts of a system. The manner in which each of these types operates has one thing in common: any virus has to be executed in order to operate. Most viruses are pretty harmless. The user might not even notice the virus for years. Sometimes viruses might cause random damage to data files and over a long period they might destroy files and disks. Even benign viruses cause damage by occupying disk space and main memory, by using up CPU processing time. There is also the time and expense wasted in detecting and removing viruses.

Viruses don not just appear, there is always somebody that has made it and they have own reason to so. Viruses are written everywhere in the world. Now when the information flow in the net and Internet grows, it does not matter where the virus is made. Most of the writers are young men. There are also few university students, professors, computer store managers, writers and even a doctor has written a virus. One thing is common to these writers, all of them are men, women do not waste their time writing viruses. Women are either smarter or they are just so good that never get caught.



Why do people write and spread viruses?

It is difficult to know why people write them. Everyone has their own reasons. Some general reasons are to experiment how to write viruses or to test their programming talent. Some people just like to see how the virus spreads and gets famous around the World. The following is a list from news group postings alt.comp.virus and tries to explain why people write and spread viruses...

• they don't understand or prefer not to think about the consequences for other people


• they simply don't care


• they don't consider it to be their problem if someone else is inconvenienced


• they draw a false distinction between creating/publishing viruses and distributing them


• they consider it to be the responsibility of someone else to protect systems from their creations


• they get a buzz, acknowledged or otherwise, from vandalism


• they consider they're fighting authority


• they like 'matching wits' with anti virus vendors

How viruses spread out

Viruses mission is to hop from program to other and this should happen as quickly as possible. Usually viruses join to the host program in some way. They even write over part of the host program. A computer is infected with a boot sector virus if it is booted from an infected floppy disk. Boot sector infections cannot normally spread across a network. These viruses spread normally via floppy disks which may come from virtually any source:

• unsolicited demonstration disks


• brand-new software


• disks used on your PC by salesmen or engineers


• repaired hardware

A file virus infects other files, when the program to which it is attached is run, and so a file virus can spread across a network and often very quickly. They may be spread from the same sources as boot sector viruses, but also from sources such as Internet FTP sites and newsgroups. Trojan horses spread just like file viruses. A multipartite virus infects boot sectors and files. Often, an infected file is used to infect the boot sector: thus, this is one case where a boot sector infection could spread across a network.

What to do when you find viruses

First thing what you should do when you find virus is count to ten and stay cool. You should keep notes on what you do and write down what your virus programs and you computer tells you. If you are not sure what to do, you should call the administrator for future action. In some cases it is not good to start you computer from hard disk, because the virus may active and then do some harm.
Second,make sure that you should get sure that it is virus and what virus it is. It is important to know what kind of virus we are dealing with. Companies that make anti-virus programs knows what different viruses does and you can ether call them and ask about that viruses or you can go to their web pages and read about the virus you have.
When you start you computer you should do it from a clean (non-infected) floppy diskette and after that run the virus program. The boot diskette should be write protected so that virus can not infect the boot diskette too. It is good to take a backup of the file that was infected. Virus program could do some damage to the file and that is why it is good to have a backup. It is good to let you administrator to know about the virus, so viruses would not spread around so much. In TKK PC classes are protected by anti-virus program and that virus program reports to a person, responsible for virus protection.

There are three different kind of anti-viral packages: activity monitors, authentication or change-detection software, and scanners. Each type has its own strengths and weaknesses. Commercial anti-viral programs have a combination of the above mentioned functions. There are over ten good anti-viral programs. Most knows programs are Data Fellows F-Prot, EliaShim ViruSafe, ESaSS ThunderBYTE, IBM AntiVirus, McAfee Scan, Microsoft Anti-Virus, Symantec Norton AntiVirus and S&S Dr Solomon's AVTK.

In conclusion, There are lots of viruses in the world and new viruses are coming up every day. There are new anti-virus programs and techniques developed too. It is good to be aware of viruses and other malware and it is cheaper to protect you environment from them rather then being sorry.There might be a virus in your computer if it starts acting differently. There is no reason to panic if the computer virus is found.It is good to be a little suspicious of malware when you surf in the Internet and download files. Some files that look interesting might hide a malware. A computer virus is a program that reproduces itself and its mission is to spread out. Most viruses are harmless and some viruses might cause random damage to data files.