Computer Viruses and Its Type

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 Computer Viruses and Its Type

What is a Computer Virus ?
A potentially damaging computer programme warm of reproducing itself causing permitted treat badly to files or added programs without admission or knowledge of the user.

Types of viruses :-
The exchange types of viruses are as follows-

1 ) Boot Sector Virus :- Boot sector viruses contaminate either the master boot collection of the hard disk or the floppy determination. The boot autograph album program held liable for the booting of effective system is replaced by the virus. The virus either copies the master boot program to option share of the hard disk or overwrites it. They pollute a computer following it boots taking place or later it accesses the dirty floppy disk in the floppy dream. i.e. Once a system is mixed assign support to on a boot-sector virus, any non-write-protected disk accessed by this system will become misrepresented.

Examples of boot- sector viruses are Michelangelo and Stoned.

2) File or Program Viruses :- Some files/programs, following executed, load the virus in the memory and doing predefined functions to contaminate the system. They pollute program files also extensions later than .EXE, .COM, .BIN, .DRV and .SYS .

Some common file viruses are Sunday, Cascade.

3) Multipartite Viruses :- A multipartite virus is a computer virus that infects fused every substitute get-up-and-go platforms, and remains recursively infective in each direct. It attempts to violent behavior both the boot sector and the executable, or programs, files at the same period. When the virus attaches to the boot sector, it will in slant comport yourself the systems files, and gone the virus attaches to the files, it will in direction make polluted the boot sector.
This type of virus can as regards-taint a system on intensity of and more than bearing in mind as well as again if all parts of the virus are not eradicated.

Ghostball was the first multipartite virus, discovered by Fridrik Skulason in October 1989.
Other examples are Invader, Flip, etc.

4) Stealth Viruses :- These viruses are stealthy in birds means it uses various methods for hiding themselves to avoid detection. They sometimes cut off themselves from the memory temporarily to avoid detection by antivirus. They are somewhat well ahead to detect. When an antivirus program tries to detect the virus, the stealth virus feeds the antivirus program a tidy image of the file or boot sector.

5) Polymorphic Viruses
:- Polymorphic viruses have the accomplish to mutate implying that they adjust the viral code known as the signature each era they go ahead or pollute. Thus an antivirus program which is scanning for specific virus codes unable to detect it's presense.

6) Macro Viruses :- A macro virus is a computer virus that "infects" a Microsoft Word or same application and causes a sequence of happenings to be performed automatically considering the application is started or something else triggers it. Macro viruses tend to be surprising but relatively harmless.A macro virus is often build uphill as an e-mail virus. Well-known examples are Concept Virus and Melissa Worm.