20 Computer Viruses And Their Types

Computer Viruses come in many forms and created with different intentions. Some corrupt or delete your computer files while others designed to replicate until they use your RAM; rendering your computer unable to operate. In this blog, we will show you everything you want to know about computer viruses and their types.

If you are new to our channel, we recommend you to read our blogs How to speed up your PC/Laptop and How to defrag your windows. These two blogs will help you speed up your computer.

What is a computer virus?

A computer virus is a piece of code to which is capable of copying itself and typically has a detrimental effect to your PC, such as corrupting the system, destroying data or gathering personal information. That code can be as little as one line, or as large as a complete program.

A virus is a type of malware, which stands for malicious software. It is a software that damages system files, copy data, crash a computer or infect multiple devices on a network.

The computer virus usually spreads through email attachments, instant messages, or direct connection with infected hard drives. They can hide in attachments of greeting cards, funny images, or latest software files.

Computer viruses also infect through cloaked downloads from the Internet. So be carful and make sure when you are downloading a file from the internet to get it from a legitimate source.

Types of Computer Viruses

These viruses are very dangerous and can harm instantly your PC/Laptops. All these are different types of computer viruses which have the capacity to harm or even destroy your computer. Read the virus description and identify infected files/folders on your PC/Laptops. After your find  the file/folder, instantly delete them from your PC.

1. Overwrite Virus

Overwrite virus is famous by the aspect that it deletes all the data. The only way to get rid of overwrite virus is to delete the infected files immediately and permanently. By which you also lose the data or information contained in those files.

2. Resident Virus

Resident Virus is one that perpetually lives in the RAM of computers. From there it is capable of overriding and interrupting all the operations executed by the physical memory. Most common signs of the resident virus include corruption of data, random opening and closing of different files, and copying or renaming of files.

3. Multipartite Virus

Multipartite viruses spread through media files and hide in the physical memory of computers. Gradually it moves to boot system of the hard disk and infects the files in it and later the whole processing unit in the desktop. A multipartite virus; also called a hybrid virus, requires a complete reset of the system for it to  eradicate.

4. Directory Virus

Directory or Cluster virus changes the address which indicates the location of any file. Sometimes by opening a file with .com or .exe extensions. You are actually executing a virus file while the original file has been moved by the directory virus. Once infected it is impossible to locate the infected files.

5. Direct Action Virus

The primary purpose of direct action viruses is to copy and take action when executing a program. When the the virus meets specific condition, it infects the files in the directory. Direct action virus mostly located in root directories of the hard drive and carries out its operation when the computer starts.

6. Non-resident Virus

Non-resident viruses are a bit similar to resident viruses in using replication of program modules. In addition to that, it also works as a finder module that can infect files when it finds one.

7. Boot Virus

These types of viruses affect the boot system of hard drives. It is a vital part in which all the information on the disk is stored with a program that is used to boot the computer from the disk. The best way to avoid boot virus is to make sure no unknown storage device is connected while starting the computer. Using write-protected hard disks can also help evade boot virus attacks.

8. FAT Virus

FAT (File Allocation Table) virus is a part of disk used in transmitting data and play a crucial role in normal functioning of computers. This virus attack can prevent you from accessing certain parts of the drive where important files might have been stored. The damage caused by a FAT virus is permanent and non-reversible.

9. Polymorphic Virus

Polymorphic viruses use algorithms and encryption keys to encode themselves differently each time they infect a new system. This makes it almost impossible for anti-virus programs to find them using signature or string searches. Polymorphic Virus also enables them to generate innumerable copies of themselves and spread faster.

10. Macro Virus

Macro virus attacks and corrupts files created using programs or applications containing macros. These mini-programs actually help the user by carrying out a series of operations as a single one. This saves the users from having to perform them one by one.

11. Email Virus

Email viruses are sort of macro virus only. It usually infects computers when opened by the recipients. For example, the user might be asked to download a gift voucher attached to the email.  This attachment always turns out to email viruses sent to infect your computer.

12. Companion Virus

Companion viruses are a type of file infector viruses like resident and direct action virus types. These are called “companion viruses” because once they infiltrate the computer system they start “accompanying” files that already exist in the system. To make it simple, we can say that in order to carry out their functions, companion viruses wait in the physical memory for a program to run and then latches onto it.

13. File Infectors

Like directory virus, file infectors also attack programs files with .exe and .com extensions. When one of these types of programs run by the user, file infectors get activated and cause the damage they are programmed to do. Most of the virus usually detected in home networks are of this nature and can be further classified on the basis of function they are encoded to carry out.

14. Encrypted Virus

Encrypted viruses are the type of virus that contains malicious codes for decrypting modules. They use encrypted codes that make basic anti-virus software programs impossible to detect them. Even advanced antivirus software can detect them only when they decrypt to spread to other computers.

15. Stealth Virus

Stealth virus is a special type of virus that tries to trick antivirus software programs by diverting its requests and messages from the user. It also has the capacity to conceal itself from basic anti-virus applications.

16. Network Virus

Network viruses use internet and LAN (Local Area Networks) to spread its infectivity. They usually multiply through shared network connections like shared folders and drives. When a network virus infects one computer, it searches for network connection to find new potential preys. Once the virus finishes corrupting the data in a computer. It moves on to the next one and repeats the cycle.

17. Sparse Infectors

A virus must avoid detection at early stages in order to spread effectively. To minimize the chances of its detection by antivirus programs a virus can use numerous methods. For example, it might only affect every 10^th time a file is executed. Or only affect files executed for a specific period of time or files with names beginning with a certain letter of the alphabet. This is what sparse infectors do. Often attached with deadly viruses, sparse infectors help them avoid being discovered at early stages.

18. Logic Bombs

Logic bombs are not really a virus because they don’t spread by multiplying. In fact, they aren’t even separate programs but rather disguise themselves with fragments of other programs. Their purpose is to corrupt and delete data on the computer when they meet certain circumstances. These bombs stay undetected until launched so the results can be extremely destructive.

19. Cavity Virus

Unlike most virus programs that go easy when infecting files, cavity virus takes the clever way. Many application and program files have vacant spaces in them. These vacant spaces are where viruses hide. A cavity virus installs itself in the spaces while not affecting the program itself. The basic point of this kind of virus is that it doesn’t increase the size of programs and can avoid detection from anti-virus software.

20. Worms

A worm is not precisely a virus, though it has the ability to spread by self-replicating itself and can cause adverse effects on your system.

21. Trojan Horses

Trojan Horses or Trojans are also not actually a virus but are capable of corrupting files and data. Though, unlike worms, they do not spread by multiplying or infecting through drives.

22. Web Scripting Virus

Many websites include composite codes to create appealing and interactive content. These codes often used to spread undesirable programs into the computers. Their main source is browsers and web pages.

23. Browser Hijacker

Browser hijackers can cause entering any particular internet URL bounce the user to multiple websites. These hijackers can attach themselves to toolbars of browsers and free download options. A good way to avoid them is to stay away from appealing free downloads and extensions. Reliable antivirus programs can also detect them quite easily.

All these computer viruses and their types that we went through are very dangerous and can harm instantly your PC/Laptops. Again, you can check the virus description and remove it from your PC/computer. We also shared links for some of our affiliates that can help you with antivirus protection, backup and more. While you enjoy the best offers we captured for you, we receive a credit to keep our business going.

Do share this blog and help your friends understand types of computer viruses and delete all infected files. Please add your comments below and share your experience with us or carry the discussion over to our Facebook, Pinterest, Instagram, MeWe or Tumbler. If you haven’t subscribed yet, go ahead and do that and you will receive “10% OFF” discount code on your favorite products.