Computer Virus

What is a computer virus?

A computer virus is a small piece of code, which is capable of attaching itself with a host file and can be easily spread by means of, e-mails attachments, flash drives, and etc. and that code causes harm to computers. Whenever the infected file is opened, the virus in it gets activated and then replicate itself and infect other data and files on computer. A computer virus is capable to brick the system, steal confidential data, and damage the computer.

The full list of virus that exist in a computer are:


They are able to fix themselves and hides in the RAM of our computer. They generally gets activated each time the Operating System loads and eventually infects other files that are opened in the system.

Memory resident virus includes:

  • Randex
  • CMJ
  • mrKlunky
  • meve


These type of virus always changes their position, but generally resides in the computer’s hard drive. Whenever a prerequisite condition is met, they get activated, and starts to affect the files in the same directory.

Direct action virus includes:

  • Vienna virus


They are the virus that are found in web pages that are either meant for spreading the virus or contains some errors in the codes which causes a virus to get evolved. These virus gets into the computer when you open the web page and download something through that site, the virus attaches with that host file and able to enter in the computer

Web script virus includes:

  • Fortnight


These types of virus works similar to direct and memory resident virus, but when they are inside the computer they accompany other existing files.

Companion virus includes:

  • Strator I096
  • Terrax I096
  • Asimov I539


This is a program that acts similar to virus, it has capabilities of self-replicating and causing damage to computer system

Worm virus includes:

  • D
  • B
  • F
  • C
  • Mapson


E-mail virus resides in the e-mail or can be spread through e-mail, whenever the recepient opens the mail which contains virus, then the virus spreads quickly inside the computer and hides/attaches itself with other files.


These types of virus manipulates and controls the booting time of the system, and is responsible for fast booting, slow booting or even unnecessary booting of computer.

Boot infectors includes:

  • The brain virus


These are the virus that infects the macro files on your computer that are implicitly or explicitly created by either the user or by any program to save content. This virus infects the macro file by changing the content and behaviour and finally attaches to that file.

Macro virus includes:

  • Relax
  • Mellisa.A
  • Bablas
  • 097M/Y2K


These are the type of virus that makes the infected file completely useless – without changing the size, it erases it’s content and damage the file completely

Overwrite virus includes:

  • Way
  • Reboot
  • 88.D


These types of virus stay’s in a disk and does not change their position too often. They harm the directory of the file by changing it’s path that indicates the location of the particular file.

Directory virus includes:

  • Dir-2 virus


These are some different types of virus which does not affect the Hard disk of computer and their action varies according to the operating system installed. They usually hides in the memory of computer.

Multipartite virus includes:

  • Tequila
  • Flip
  • Invader


These are the special type of virus, which attack only FAT (File Allocation Table). These virus can be very harmful since they attack the file which contains all the important details about the computer like free space, size and location of memory etc.

FAT virus includes:

  • Link virus


These are the virus which do not get caught easily by an anti-virus, since they uses different algorithm and encryption technique each time they infect any file.

Polymorphic virus includes:

  • Tuareg
  • Elkern
  • Marburg
  • Satan bug


Trojans are the most dangerous virus, it is directly used by hacker to steal confidential data and files to get unauthorized access to their data. For example someone’s computer is affected by Trojan virus and that person is using the bank account for transferring the money, then the person controlling the Trojan, can simply gain the access to the persons account as it have all the necessary information that is needed to log into the account.


This is a type of virus which is usually resides in the memory of computer and is responsible for the control of any web browser, it redirects the page to some other sites or to download any content or even it opens the browser automatically and starts to load any page.

Browser hijacker virus includes:

  • Cool web search

Make sure guys that your anti-virus is up to date and provides you better security.

So these are all possible types of virus! If you guys know some other computer virus, then please let me know by commenting below in the comment section. Stay protected, stay safe!