Main types of computer viruses

From the article «what is a virus» you know a bit about viruses. Today I suggest to talk about the types of viruses. There are quite a number of viruses. There are different classifications, and each of them has some differences. So my list is only main types of computer viruses. Maybe I will, if possible, its complement. All the more so that the bad guys constantly improving technology, and invent something new -).

So the main types of viruses:

Resident Viruses
This type of virus is a permanent which dwells in the RAM memory. From there it can overcome and interrupt all of the operations executed by the system: corrupting files and programs that are opened, renamed, copied etc.

Boot sector viruses
One of the most ancient types of computer viruses. Boot sector viruses infect the boot record on hard disks, floppy оr other disks. This type of virus does not need to be able to successfully boot the victims computer to infect it.

Master Boot Record (MBR) viruses
MBR viruses which infect the Master Boot Record on fixed disks and the DOS boot sector on diskettes. All common boot sector and MBR viruses are memory resident.

File infector viruses
This type of virus infects programs or executable files (.EXE or .COM extension). Though some can infect any program for which execution or interpretation is requested, such as SYS, OVL, OBJ, PRG, MNU and BAT files. When one of these programs is run, directly or indirectly, the virus is activated, producing the damaging effects it is programmed to carry out. The majority of existing viruses belong to this category, and can be classified depending on the actions that they carry out.

Macro viruses
Macro viruses infect certain types of data files. Most macro viruses infect Microsoft Office files (such as MS Word Documents, Excel Spreadsheets, and other).
Macro viruses use the Visual Basic macro language which is built into Microsoft applications. Continual use of the program results in the spread of the virus. Some macros replicate, while others infect documents.

Multi-partite viruses
Multi-partite may fall into more than one of the top classes. For example, a multi-partite computer virus might infect both the boot record and other files.

Polymorphic Virus
Polymorphic viruses encrypt or encode themselves in to avoid detection from anti-virus software.

It was a story about the main types of computer viruses. In subsequent publications we will talk about how viruses work, how they find and get rid of them.

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