author: Maka Saparashvili
Introduction to Computer Viruses
The person might have a computer virus infection when the computer starts acting differently. For instance getting slow or when they turn the computer on, it says that all the data is erased or when they start writing a document, it looks different, some chapters might be missing or something else ubnormal has happened. The next thing usually the person whose computer might be infected with virus, panics. The person might think that all the work that have been done is missing. That could be true, but in most cases viruses have not done any harm jet, but when one start doing something and are not sure what you do, that might be harmful. When some people try to get rid of viruses they delete files or they might even format the whole hard disk like my cousin did. That is not the best way to act when the person think that he has a virus infection. What people do when they get sick? They go to see a doctor if they do not know what is wrong with them. It is the same way with viruses, if the person does not know what to do they call someone who knows more about viruses and they get professional help. If the person read email at their PC or if they use diskettes to transfer files between the computer at work and the computer at home, or if they just transfer files between the two computers they have a good possibility to get a virus. They might get viruses also when they download files from any internet site. There was a time when people were able to be sure that some sites we secure, that those secure sites did not have any virus problems, but nowadays the people can not be sure of anything. There has been viruses even in Microsoft's download sites. In this report I am going to introduce different malware types and how they spread out and how to deal with them. Most common viruses nowadays are macro viruses and I am going to spend a little more time with them. I am going to give an example of trojan horses stealing passwords.
General information about computer viruses
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: 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.
A Trojan Horse is a program that does something else that the user thought it would do. It is mostly done to someone on purpose. The Trojan Horses are usually masked so that they look interesting, for example a saxophone.wav file that interests a person collecting sound samples of instruments. A Trojan Horse differs from a destructive virus in that it doesn't reproduce. There has been a password trojan out in AOL land (the American On Line). Password30 and Pasword50 which some people thought were wav. files, but they were disguised and people did not know that they had the trojan in their systems until they tried to change their passwords. According to an administrator of AOL, the Trojan steals passwords and sends an E-mail to the hackers fake name and then the hacker has your account in his hands.
A worm is a program which spreads usually over network connections. Unlike...