Types Of Computer Viruses: A Comprehensive Guide For 2021


A computer virus is a malicious program that copies itself into another program to reproduce itself. To put it another way, the types of computer viruses replicate themselves by infecting other executable code or documents. A computer virus aims to infect vulnerable systems, gain administrative power, and steal sensitive data from users. Hackers create different types of computer viruses and worms with malicious intent and use deception to prey on internet users.

Opening an attachment in an email, visiting an infected website, clicking on an executable file, or watching infected advertising are all good ways for viruses to spread to your device. Infections, on the other hand,

Infections can also spread when users link to contaminated removable storage devices, such as USB drives.

Malware can easily infiltrate a machine by eluding the security mechanisms. An effective breach can infect other resources or system software, alter or uninstall key functions or programs, and copy, delete, or encrypt data, among other things.

In 1971, Robert Thomas, an engineer at BBN Technologies, created the first documented computer virus. The first virus was dubbed “Creeper,” and Thomas’s experimental software infected mainframes on ARPANET. “I’m the creeper: Catch me if you can,” read the teletype message on the screens.

Fred Cohen coined the word “computer virus” in 1983, after a year of study. When he attempted to write an academic paper titled “Computer Viruses – Theory and Experiments” outlining the malicious programs in his work, he coined the term.

  1. List of different types of computer viruses
  2. Ways to prevent computer viruses and different types of security threats 
  3. Virus Infection Symptoms after malware attack 

1.List of different types of computer viruses

A computer virus is a form of malware that incorporates its virus code into programs and applications to multiply itself. Malicious code is repeated on the computer, infecting it. Software viruses come in several shapes and sizes, and they infect the system in various ways. Here are a few of the most popular types of computer viruses.

  • Virus in the Boot Sector
  • Virus with Direct Action
  • Multipartite Virus Resident Virus
  • Virus with Polymorphic Forms
  • Virus Spacefiller 
  • Boot Sector Virus – This type of virus infects the master boot record, and removing it is a difficult and time-consuming process that often necessitates the machine being formatted. It primarily spreads via removable media.
  • Direct Action Virus – Also known as a non-resident virus, this type of virus installs itself or hides in the computer’s memory. It remains attached to the same file types it infects. It has no effect on the user’s experience or the system’s performance.
  • Resident Viruses – Unlike direct action viruses, resident viruses stay on the machine after being mounted. It is difficult to recognize the virus and much more difficult to eradicate a virus that has become resident.
  • Multipartite Virus – This virus can spread in a variety of ways. It simultaneously infects the boot sector and executable files.
  • Polymorphic Virus – Conventional anti-virus systems have a hard time identifying these viruses. This is because as polymorphic viruses multiply, their signature pattern changes.
  • Overwrite Virus – When this form of virus infects a computer, it deletes all of the files it infects. The only way to eliminate it is to uninstall the infected files, which means the end-user will lose all of the files’ contents. The overwrite virus is difficult to detect because it spreads via email.
  • Spacefiller Virus – Also known as “Cavity Viruses.” This is because they fill in the blank spaces between the text lines, preventing the file from being damaged.

2.Ways to prevent computer viruses and different types of security threats

  • Make use of a professional email service like Runbox. Subscription-based services provide greater security and support.
  • Check that your Runbox Trojan malware/virus filter is turned on.
  • Read your email using the Webmail interface at www.runbox.com rather than downloading it all to an email client. Before downloading the valid email to your local email client, screen your email and remove any suspicious-looking or unwanted messages.
  • Make sure your anti-virus software is up to date and running locally on your computer. For effective virus security, automatic updates are needed. You now have two levels of protection when you combine client-side scanning with server-side scanning.
  • Especially on Windows platforms, disable message preview in your email client. Otherwise, malicious programs attached to incoming messages can run and infect your machine automatically.
  • Ignore or delete messages that appear to have been sent from official Runbox email addresses and include attachments. Aside from responses to inquiries and payment notifications, Runbox seldom sends an email to its users. We seldom send users an email with attachments.
  • Be cautious when opening graphics and media attachments, as viruses can disguise themselves as these types of files.

3.Virus Infection Symptoms after malware attack

Any computer user should be aware of the malware attack after the following warning signs –

  • Slower system output
  •  Pop-ups bombarding the screen
  •  Programs running on their own
  • Files multiplying/duplicating on their own
  • New files or programs in the machine
  • Lost or damaged files, directories, or programs


This means that a virus will stay dormant on your machine for long periods without causing any noticeable symptoms. Once a virus has infected your computer, it will spread to other computers on the same network. Taking passwords or records, logging keystrokes, corrupting files, and spamming your email contacts are examples of cybercrime.

So, have you made up your mind to make a career in Cyber Security? Visit our Master Certificate in Cyber Security (Red Team) for further help. It is the first program in offensive technologies in India and allows learners to practice in a real-time simulated ecosystem, that will give them an edge in this competitive world.


Related Articles

Please wait while your application is being created.
Request Callback