Recent development in the computer industry has created lots of security issues involved with it. Main type of threat is a virus. Virus can be considered as a program that spreads unwanted and unexpected actions inside the computer. It is much more like a biological virus, since it spreads when it is initiated. Many of these virus programs are designed to damage files, applications and operating systems. It is the intention of the program which decides whether it is a virus or not.
This is the reason why all the computer users in the world are now keen on getting a virus scanner installed in the computer. These anti virus soft wares can protect the computer from viruses, worms like Zafi, Mydoom and many more. Even though everyone knows the importance of an anti virus software, most of them are confused in which one to choose. It is after all an investment that the user is going to make. That is where this guide will help the computer users in all around the world.
Let’s have a good look at the viruses first. Boot sector viruses, macro viruses and file infecting viruses are the three main types of viruses.
Boot sector is considered to be the first sector in a floppy disk or hard disk. These sectors will contain all the details required for a computer to boot to its operating system. Every time the system is booted, these files will be used. Formatting the disk will rewrite all the boot data in the disk. It has a high chance of getting attacked by viruses as well. For example if an infected floppy disk is left on the disk drive when the system restarting, the infection will get into the hard disk boot sectors as well. After that it will be spreading in the hard disk as well as external devices which will be connected to the system after that. This can lead to a boot failure also.
Second type is the macro viruses. This type of viruses accounts for almost 75 percent of viruses around the world. They can come thorough either data storage devices, networks or mostly the internet. Macro viruses will not attack applications directly. The will affect the internal macro programming languages used in programs such as Microsoft Excel or Word. When these infected files are opened, it will spread to other files also. If the files are shared, it can affect other computers also.
The third type is the file infecting viruses. This type of virus will attack the executable and command files in a system. When the infected file is executed it will spread to other attached files as well in that process. The affect of infection will depend on the intensions of the person who developed the virus. Virus may be written to destroy files, overwrite boot sectors or to install a backdoor program. Viruses which will install backdoor programs are called zombies and they will give access of the computer to the virus creator. This is considered to be a criminal act.