Resident Virus: How They Work, and How to Protect Yourself

Updated: August 30, 2023 by Ashley Haugen

Key Points

A computer virus is defective code which is meant to replace the actual code in your device to enable hackers to damage your memory.
A resident virus is one which infiltrates the disc or drive of your device, and may even infect any other disc or drive connected to it.
It is also capable of accessing any files or folders on compromised drives and may even render the antivirus ineffective.

Your computer starts to slow down. Files begin disappearing. Your storage randomly fills up without explanation. Then, your screen goes blue. Before long, it’s totally black. This is the work of a computer virus, and it has just wreaked havoc on your desktop, laptop, or even your tablet or cell phone. How did this happen? And what kind of protection can be enforced to make sure it doesn’t happen again?

In order to understand the dangers of a computer virus and how to protect yourself from an infection, it’s worth discussing what exactly a computer virus is, what the different types of computer viruses are, and how to keep one of the most dangerous forms — the resident virus, or memory-resident virus — from infiltrating your computer memory.

What Is a Computer Virus?

In simple terms, a computer virus is a program that hopes to infect other computer programs and replace healthy code with its own destructive code. If this code infection takes place, the computer virus is free to unleash any number of dangerous programs on unsuspecting victims the world over.

There’s no such thing as a healthy or good computer virus. They exist solely to help aid hackers and cybercriminals bring infection and destruction to people’s computer memory in hopes of getting something in return. Whether it be personal information such as your name, address, or social security number, financial information like your bank account or credit card information, or even private information such as your own photos, videos, and texts, the list of dangers of an infection from a computer virus could go on and on. That’s why it’s important to have protection — both for you and your computer memory.

Computer Virus Types

Below, we’ve listed an assortment of the most common types of computer viruses, also known as malware. While these are the most commonly seen across the globe, they are by no means the only types. Hackers and cybercriminals are almost constantly scheming up new viruses and malware to get your information, making it difficult to truly index them all. The list below is merely a good start.

Browser Hijacker Virus: a software that alters your browser’s settings, appearance, or behavior without you knowing. A browser hijacker hopes to generate ad money for the hacker or cybercriminal and might even attempt to collect your data, passwords, or keystrokes to take further advantage of victims.
Direct Action Virus: a virus that attaches itself to otherwise reputable or trustworthy files or programs. After installing or opening the virus-laden file, the virus spreads throughout the computer in search of valuable info. This is also known as a Trojan horse virus.
Worm Virus: a malware program that takes advantage of weak points in your device’s security and exploits them to steal your personal info. Worms build their own backdoors to your system, making it easy to continue to access and wreak havoc on your devices again and again.
Spyware Virus: a software that secretly tracks your online activity without you knowing about it. As it secretly gathers your information, it then uses or sells this information to further exploit your finances or personal info.
Adware Virus: a series of pop-up advertisements on your device that hope to either convince you to give up your personal info or simply rack up ad revenue from your continued views.
Resident Virus: also known as a memory-resident virus, this is a malware that embeds itself inside your computer memory and subsequently infects any and every file run by the computer.

How Does a Resident Virus Work?

The resident virus — or the memory-resident virus, depending on the person — works by attaching itself to a drive or disk and storing itself inside the computer’s memory. From there, it is allowed access to all the files and programs on the computer. What’s more, it could spread to any other drive or disk linked to the computer.

What’s more, the resident virus can even attach itself to the computer’s anti-virus software — not only does this grant it access to each and every file the program scans, but also renders the anti-virus software powerless.

Resident viruses can be either fast or slow infectors, and the amount of damage varies depending on which one you’re dealing with. As you might expect, fast infectors wreak havoc quickly and mercilessly (thus making them far easier to detect), while slow infectors are a little more subtle and do their damage a little less obviously.

virus detected — *There are many types of computer viruses but a resident virus embeds itself in computer memory.*

Dangers of a Computer Virus

Just like how it’s important to stay in tune with your body, it’s vital that you regularly perform check-ups on your computer, as well. The dangers of a computer virus are vast and seemingly endless, and you don’t want to be left having to deal with one if you can prevent it. Some of the most prominent dangers associated with a virus are as follows.

Damaged, missing, or corrupted files: When a virus attaches itself to your hard drive, it can render your documents, your photos, your applications, and anything else saved to the drive useless. Worst of all, it’s unlikely you’ll be able to recover them.
Stolen information: One of the primary goals of a computer virus is to gain access to important information. Whether it be personal, financial, or professional information, hackers and cybercriminals want their hands on it. A computer virus can help them get it.
Decreased performance: While this is undoubtedly the least of a person’s problems when files are being destroyed and information is being stolen, viruses can also slow down your computer’s overall speed. This impacts your device’s performance and makes everything move noticeably (and annoyingly) slower.

Protection from Resident Viruses

There are several different tips and tricks you can enact to protect yourself from a resident virus (or any other computer virus, to be honest). Here are five places you can start:

Keep software current and up to date.
Don’t click unfamiliar links and avoid unauthorized downloads.
Use antivirus software, firewalls, and pop-up blockers.
Routinely back up your devices.
Use strong passwords and password managers.

Are you interested in learning about other computer viruses? Check out our complete guide!

In the video below from YES_info, you’ll learn about viruses, how they work, and important information you should know.

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Resident Virus: How They Work, and How to Protect Yourself FAQs (Frequently Asked Questions)

How do resident viruses work?

A resident virus — or memory-resident virus — works by latching itself onto the computer’s memory, thus granting it the freedom to attack any file or application on the device (including the anti-virus software).

How can resident viruses be prevented?

Resident viruses can be prevented by using antivirus software, pop-up blockers, and firewalls. What’s more, you can further prevent resident viruses by keeping your software as up-to-date as possible and routinely scanning your computer for any viruses. Little things — such as avoiding suspicious links and downloads and using strong passwords — can also do wonders for virus protection.

How do you get a resident virus?

Resident viruses can come from corrupted drives or disks, or from suspicious links or downloads.

What does resident virus mean?

The term “resident virus” refers to the way the virus takes up residency in the computer’s memory.

What are the symptoms of a resident virus?

Some signs and symptoms of a resident virus are as follows: frequent changes to your computer or settings, decreased speed and performance, recurring crashes, unfamiliar programs running in the background, changes to your passwords, and unexplained pop-ups.

Which virus is a non-resident virus?

Non-resident viruses are any viruses that do not live in the computer’s memory.

What is the difference between a resident virus and non-resident virus?

The difference between a resident and non-resident virus is slight but distinct: While a resident virus infects applications as the user opens them, non-resident viruses can infect files and programs even when they aren’t opened.