Types of Viruses

The Virus is a type of code that enters the system along with any file or programs and carries out malfunctions in the system. The virus-affected program will be a replica of the existing program. They enter the system through any file and when the file runs, parallelly the virus also runs in the background.

There are many ways in which the virus gets into the system. Some of them are through mail attachments, by clicking inappropriate advertisements, and by downloading any software, or files from unauthorized websites. The main objective of viruses is to spread them along different hosts. They steal the personal data and other credentials of the system. The various types of viruses are depicted in this article.

Types of Virus

A virus is a type of malware and all malware are not viruses. Examples of viruses are Nimda, Trojan, Tinba, SQL Slammer, and crypto locker. Many types of viruses affect the system namely,

Boot Sector Virus

Boot sector virus enters the system using a USB drive. It is a type of malware that affects storage sectors containing startup folders. The virus enters the startup folder and execute during the booting of the operating system by inserting malicious code. So these viruses run before starting security software like antivirus.

These viruses affect during startup of operating system and damage the system completely. Operating system like BIOS and UEF1 has preinstalled security against the boot sector virus.

Examples − Elk Clones, Brain, Stoned, and Parity boot virus.

Parasitic Virus

Parasitic virus attacks the file using the extensions .exe or .com. It spreads the virus by attaching itself to another program. It is also called a file virus. The Parasitic virus hides them in a file and runs along with the file. To avoid this virus, users should avoid clicking unwanted links.

Examples − Virut, sality and vetor.

Stealth Virus

Stealth virus is computer viruses that are hidden inside a file in the operating system. It steals the data, changes the encryption of data, and undergoes a self-modification of the code. It is unnoticeable by the users and usually hide in the boot part of the system. So, it needs an updated strong antivirus and scanner software to protect the system from the stealth virus.

Example − Brain

Macro Virus

It is a type of virus coded in the macro language. The Macro language is mainly used for designing software applications. It affects only the software applications irrespective of the operating system used. As both software and the virus use the same language they enter the application and affect them.

Examples − Melissa Virus and Nuclear virus.

Polymorphic Virus

The Polymorphic virus enters the machine via infected systems, corrupted files, and emails. It affects the data, and functions and changes the encryption of the data. They have a complex design structure in such a way that any protection system could not find this virus. They get modified according to the software.


Source code Virus

The source code of the infected computer gets changed or affected. This type of virus is rare and it is very difficult to remove them when a computer is affected by it. The causes of source code virus is hijacking the machine and corrupts it.

Resident Virus

The Resident virus is a type of malware that targets the memory file of the computer system. It is considered the worst one as they get attached to the files of antivirus software and corrupt them too.

Examples − Meve, CMJ and Randex.

Tunneling Virus

The Tunneling virus finds that the antivirus is detecting it as malicious software. So it enters into the antivirus program, intercepts its function, and thus avoids running the antivirus software.

Example − Frodo.

Multipartite Virus

It is the fastest virus that affects the executables files and system boot sector simultaneously. It affects multiple parts namely the memory and the operating system.

Examples − Invader and Flip


Computer safety is very important and to do this the system should be free from malicious attacks. The attackers are emerging at a high rate to steal and phish the data for both personal and business uses. The medium for entry of viruses is divided into four ways like hardware, software, Bluetooth, email, and the internet.

Viruses are designed by hackers to corrupt or steal sensitive data from the target system. The virus is a set of codes that spreads all over the system and damages the legitimate file. Different types of viruses that affect the machine are wide and the ways to protect them are also found accordingly.

Updated on: 28-Mar-2023

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