What Is a Computer Virus and Should You Worry About It in 2022?

As technology gets more sophisticated, you may think a computer virus is a thing of the past, but they may be more worrisome today than ever before.
Patti Croft, Author
Catherine McNally, Editor
Last updated Jun 10, 2022

What is a computer virus? The simple way of thinking about a virus is that it is a malicious software program that enters your device without your knowledge. It then spreads throughout your computer and performs an attack on the network.

With technology changing so much through the years, you may not think a computer virus is anything to worry about. Unfortunately, cyber attacks are still a relevant online threat.

Many types of computer viruses can threaten the security of your device. Unlike humans, your computer cannot rest and recover from a virus. Until you remove it, the virus is there to stay.

According to the AV-TEST Institute, new malware threats have steadily risen during the past year. There can also be different ‌viruses depending on the operating system you have and the device you use.

Windows has been shown to receive more computer viruses than Mac operating systems, but that may be because of the large number of Windows machines in existence. Windows has almost 74% of the operating system market. With Macs becoming more popular, the incidence of viruses will likely increase for them as well.

No matter which device you use, ‌computer viruses are not a thing of the past. Keep reading to learn more about what a computer virus is and why you should still be concerned about online security in the modern tech age.

In this article
What is a computer virus?
Types of computer viruses
How does a computer virus spread?
History of computer viruses
How to remove a computer virus
Computer virus FAQs
Bottom line

What is a computer virus?

A computer virus is a software program that gets built with malicious intent. The purpose of the virus is to perform actions without the device user’s knowledge or consent. The program uses malicious code to complete a destructive activity on the device or network.

Computer viruses sometimes get designed to steal your private data. That could be health information or your financial data. In businesses, a computer virus can bring operations to a halt.

Sometimes viruses get created to interrupt network services. That stalls any work you might need to perform on the device. They can get into the local file system and cause damage that may be difficult or even impossible to repair.

Are malware and computer viruses the same?

Malware and viruses get thought of interchangeably at times. Malware is an umbrella term that includes spyware, viruses, worms, and any other malicious software.

Types of computer viruses

Some computer viruses may come as attachments through trial software or email. Other viruses may get replicated by video files. You should know how the different viruses work so you can protect yourself against online threats.

Boot sector virus

The boot sector portion of your computer is where the code and data to start your machine resides. The boot sector virus enters the device through an infected peripheral such as a USB drive.

Browser hijacker

A browser hijacker virus changes your regular internet browser without your consent. It can enter your device through bundled software you install or download. It can also be a link you click on that may contain an extension that changes your browser to include pop-up ads.

The hijacker gets revenue from the ads you view. Many browsers are working hard to keep online viral threats to a minimum, but using reliable antivirus is necessary to reduce the risks as much as possible.

File-infecting virus

File-infecting viruses get their name because they spread their codes to executable files. These may be .com or .exe files. These can be especially dangerous if they damage your hard drive. The damage consists of reformatting the drive and can wipe out some files completely.

You may also get warnings that your hard drive is full. The virus can replicate itself and fill up all the space on your hard drive, which means you have no more memory to spare. It will slow down all your programs and render them unusable.

Macro virus

Macro viruses enter your network by embedding code in data files. These are malicious programs that spread through documents and spreadsheets that get frequently accessed. Whenever the file gets opened, the macros get enabled and infect other files on the device.

Multipartite virus

This virus is considered one of the worst computer viruses invented because it was developed by cybercriminals to make a network’s security vulnerable because it can infect multiple times.

If you have not performed recent backups on an external device, you may lose your data. It spreads by attaching to a self-executable file and waits to get triggered. Once the .exe file runs, the virus can latch onto your hard drive and leave your device inoperable.

Overwrite virus

The overwrite virus is difficult to contain because it can destroy your original programs. It spreads by overwriting original system memory data. If you have not backed up your original programs, this virus can cause you to lose them. Once they are gone, you will be unable to retrieve them.

Polymorphic virus

A polymorphic virus is another file-infector virus. This one can be tricky because it spreads by creating different versions of itself, making it harder to detect. These viruses use multiple encryption keys and codes to vary their physical makeup.

Resident virus

A resident virus is aptly named because it hides and takes up residence in your computer memory. Depending on how the virus gets programmed, it can infect any file that the computer runs.

The resident virus can infect other files every time the operating system loads. It may be harder to delete than other viruses because it can affect the entire device’s system.

A resident virus has two kinds of infectors: slow and fast. The fast infectors do lots of damage fast but are easy to detect because of the massive infections. Slow infectors may spread further throughout the system because they won’t get detected as soon.

This virus does not have to get executed because it loads a replication module into the device’s memory. This one is particularly dangerous, as it can attach itself to an antivirus program and infect any file scanned. Your antivirus software works to safeguard your network against these threats, but you need to keep it updated to catch the latest malware.

Spacefiller virus

A spacefiller virus looks for a space or empty sections of a file. Once found, it can infect the entire file without changing the file size. That makes it harder to detect when performing a virus scan.

Trojan horse

A trojan horse works by pretending to be a legitimate file. It impersonates a different software that you may think you recognize. Once these viruses get into your computer, they can perform malicious activity.

The trojan horse virus may look like an update that you need to install for a software program you use. Instead of an update, you install malware. Some of these can give hackers remote control of your device.

Web scripting virus

A web scripting virus attacks a web browser and infects the page. Once infected, it controls your browser settings and activities. There are two kinds of web scripting viruses on the internet:

  1. Non-persistent: Infects your browser without your knowledge.
  2. Persistent: Attacks your browser settings with you unintentionally allowing it to control them.

Are keyloggers a computer virus?

Keyloggers are a type of virus called rootkit viruses. They can be particularly malicious if they infect your operating system, but some keyloggers also infect your web browser. A keylogger can be an especially dangerous type of malware since it logs your keystrokes — making it easy for someone to hijack your passwords or personal information.

How does a computer virus spread?

Computer viruses can spread through email, removable media, and internet downloads. Sometimes packaged software comes with an attached virus.

Opening emails from people or organizations you don’t recognize can make you easy prey for hackers. Often, an attachment gets included that comes embedded with a virus. You can protect your computer by knowing the reason behind any email attachment before opening it.

Removable media, like USB drives or external hard drives, are not allowed in some organizations because they can ‌spread viruses. When a device is part of a network, the computer virus can spread across the entire network before it gets noticed.

Many businesses have cracked down on computer security because of cyberattacks. In 2020, a computer virus at a health care facility forced a network shutdown, costing millions of dollars.

Packaged software and internet downloads can have hidden viruses embedded. You may install a program or update you needed and not realize a virus lurks in the background.

History of computer viruses

The first computer virus, Creeper system, dates back to 1971. Even though the internet as we know it didn’t exist, viruses were invented to steal information or test processing power and ability. Creeper was created to see if it’s possible for a computer program to self-replicate.

The first Microsoft Windows computer virus written by two brothers, ‌17 and 24 years old, was called, “Brain.” It was developed ‌to regulate the software they created, as pirates had stolen the heart monitoring software they designed. If stolen software got installed, the virus would copy itself onto the computer.

The virus to first make Apple a target was invented by Rich Skrenta, who was 15 years old then. The Elk Cloner virus was created in 1982 as a joke and would spread through the use of floppy disks. This was the first boot sector virus and every 50th time a machine rebooted, a poem would emerge on the screen.

As technology evolves, more computer viruses get created. During the COVID-19 pandemic, cybercriminals sent mass emails claiming to give updates or information on relief payments. Instead of help, the users downloaded malware.

In 2021, people who used Google may have gotten themselves into a dilemma after clicking on advertisements that hid the MosaicLoader virus. These “ads” were at the top of the search, which made them look more legitimate. Once the virus was installed, it would steal passwords and data. It could also use your computer to mine cryptocurrency.

How to remove a computer virus

The first step to removing a computer virus is to have a robust antivirus software program. The best antivirus software will offer your device protection against new and old cyber threats. You can tailor different antivirus programs to your specific needs.

Using your antivirus software, you want to run a full scan, then delete the virus or quarantine it. A full scan will cover all the hard drives of your infected computer or device. Some people use the quarantine option when they think the infected file is still salvageable. In most cases, deleting the file may be the safest option.

Next, delete any temporary files and clear your browser history. Sometimes sneaky viruses hide in these temporary files. Many of us don’t think about these files, but hackers do because of the files’ lax security. You can read more on recognizing and removing viruses to know you’re checking all the spots a virus can reside.

Computer virus FAQs


What are the 10 most common types of computer viruses?

Unfortunately, viruses can sneak onto almost any device, and some are more prevalent than others. Here are ten of the most common computer viruses:

  1. Macro virus
  2. Boot sector virus
  3. Trojan horses
  4. Overwrite virus
  5. Browser hijacker virus
  6. Web scripting virus
  7. Polymorphic virus
  8. Resident virus
  9. Multipartite virus
  10. Spacefiller virus


What was the first computer virus?

The first known computer virus was the Creeper system created in 1971.


Who named the first computer virus?

Bob Thomas named the first computer virus after a Scooby-Doo character.


Who created the first computer virus?

Bob Thomas created the first computer virus for BBN Technologies in the U.S.

Bottom line

A computer virus is a software program that is usually designed with malicious intent. It spreads through a computer by email, peripheral devices, and internet browsers. With more viruses getting created every day, these threats are still relevant.

Consider the number of emails you access throughout the week. Most are harmless, but some are not. If you use a USB drive to save and transport data, your computer could be at risk of receiving a nasty virus.

As an informed computer user, a little preparation will pay big dividends for cybersecurity. For the most advanced and up-to-date antivirus software, be sure you follow our site. You can learn more about how computer viruses work to keep from being the next target.

Author Details
Patti Croft
Patti Croft has a B.S. in Computer Information Systems and an MBA. She's also a Certified Health Data Analyst through the American Health Information Management Association (AHIMA). Patti worked in Information Technology for 16 years and loves everything tech and gadgets!