10 common types of computer viruses

10 common types of computer viruses

Virus, malware and hacking are inter-related. The first one can devastate one program or your whole computer system. Viruses are commonly known for eradicating important files, putting your data at risk or needing a hard drive reformat to get the computer to work again.

Learning how to protect your PC or your laptop is quite important, but you will also need to understand what to protect them against and that’s exactly what we are going to explain here.

There exist more than 100,000 known computer viruses, which means a serious threat to your computer. However, only a small part of them live in the wild, so with this guide we will explain 10 common types of computer viruses and how the infect and affect your system.

10 common types of computer viruses

Overwrite Virus

At the very top of this list we find the overwrite virus. It doesn’t matter if your operating system is Macintosh, Linux, Windows or DOS, since this virus is quite effective on all of them. As you can imagine by its name, this virus deletes partially or totally the data and exchanges it the existing code with the malicious one.

Luckily, this virus can be easily detected because the program stops working, but it’s important for you to know that as soon as this virus infects the file, the data can’t be restored and it will be lost.

Boot Sector Virus

This is one of the most dangerous virus in the wild because its infection affects the master boot record, meaning that it’s not easy to remove, usually needing a full system reformat. This virus encrypts the computer’s boot sector, damaging the code. The more optimistic part of this virus is that the BIOS architecture of newer PC units have improved and reduced its effectiveness.

This virus can infect your PC through the use of removable media like USB or hard drives that have also been infected.

Direct Action Virus

This virus enters into the main memory quite fast and infects all projects, folders or files defined in Autoexec.bat path. After doing this, it deletes itself. The direct action virus can change its location on every execution, which makes it quite hard to diagnose. Even if it’s an annoying virus, it doesn’t affect your system’s performance, it only makes your files inaccessible.

To delete it you will only need a basic antivirus program.

Web Scripting Virus

This virus gets into the browser security, allowing hackers to inject client-side malicious scripting into the site page. Compared to other viruses, web scripting viruses are quite easy to spread and transmit themselves into your computer’s system through the programming used for websites and making you to download he virus without knowing when you click on malicious websites’ links or videos.

To prevent this kind of virus you will need to install a security program that detect malicious coding when browsing the Internet.

Memory Resident Virus

It is one of the most destructive virus because it infects your computer memory and sets it as its base of operations, making your operating system to help the virus. It’s stablished in the main memory (RAM) and starts working when you turn on your computer.

If you want to be well protected against this virus, you will need to install a high-quality advanced antivirus.

Companion Virus

It was most famous during the MS-DOS time. It works by making a duplicate of a file with an alternate extension that runs alongside the real program. Also, when the system calls the original file, the duplicated extension will run before the original one. This way, the Companion Virus affects your system’s performance by deleting the files.

About how to protect yourself against this virus, you will also need to install a high-quality advanced antivirus and also not to download attachments from unknown email sources.

Macro Virus

A Macro Virus, as you can imagine by its name, gets written in the macro language and runs automatically when the file gets opened. It spreads quite easily to different files. This kind of virus are generally received via emails.

If you want to protect you PC against this virus, you should disable macros and delete emails from unknown sources without opening them.

Multipartite Virus

This virus remains in the memory and affects the hard disk, infecting and propagating itself in many ways and affecting mainly the operating system of your computer. The way to know if your computer is affected by this virus is to observe performance slack and the low availability of virtual memory for client applications.

To prevent this virus, clean the disk and the boot sector and, of course, like with many others viruses, install a high-quality advanced antivirus program.

Polymorphic Virus

Very hard to detect thanks to its ability to encrypt and change its coding whenever it infects a system. The best way to protect your computer against this king of adaptive coding is to install a high-quality advanced antivirus program, the only ones able to deal with a wider range of threats like this one.

FAT virus

This kind of viruses ruin your entire file allocation system, the place where exist the information about files and where to find them. FAT virus will destroy files and entire directories, so get sure to be well protected against them, again, with the installation of a high-quality antivirus.