Computer viruses are very much like biological viruses in that they are designed to spread to as many computers as possible and damage them. The word “virus” initially refers only to a code that is distributed through email attachments, removable drives, or downloads, but referred these days to all malicious software, or malware, from worms and trojans to adware and spyware, even though they don’t all have the same reproductive qualities. Let’s start from the beginning to understand what we are dealing with when encountering such mean intruders.
What Can a Virus Do?
Once a virus installs itself on your computer, its main objective is usually to spread to other programs and files and any computers connected to the same network. What it does after that varies, depending on the code, but usually significant damage is involved. Some viruses corrupt or delete data from your computer and often delete everything from your hard disk, while others attack servers with the purpose of bringing them down completely.
How Do Viruses Work?
Usually a virus will reach your computer through a file you downloaded from a website, email, or external device. That is why it is very important to never download anything from a source you don’t trust. Once it is activated, the virus will start to spread, usually without compromising the performance of the programs you’re running so you don’t even notice it’s there. Some viruses even have polymorphic code which modifies their decryption modules and changes the virus every time it reaches a new host. This is done to avoid detection by antivirus software. Some antivirus programs create what is called “bait files” in order to attract the virus and study it so that they can learn how to remove it.
There are many different types of viruses, each different in how it works, where it comes from, where it infects your computer, and what it ultimately does. Here is some more information about the most common types of computer viruses:
- Resident: These dwell in the RAM memory, putting them in a position to interrupt any operation the system executes.
- Overwrite: Overwrite Viruses infect files and overwrite the information in them, meaning you lose that information permanently.
- Direct Action: These viruses infect files in the computer’s directory and replicate themselves, usually taking a certain action when the computer boots.
- File Infectors: These infect executable files and activate when the files are run, carrying out damaging effects.
- Boot: Boot viruses infect the hard disk’s boot sector, making the computer unable to boot.
- Directory: These types of viruses alter the paths indicating a file’s location, tricking you into running the infected program unknowingly.
- Macro: Macro Viruses infect programs and cause a sequence of actions to be performed when the infected programs are run.
- Browser Highjack: Technically these are called PUP (potentially unwanted software), and not actual viruses. In most cases, they change the homepage and default search engine in the browser and it is usually very difficult to remove them or restore the original settings.
How Do You Protect Yourself?
Most viruses today can be caught or avoided if you follow three simple instructions:
- Get a good antivirus program installed on your computer
- Make sure your operating system and browser are updated
- Only download files from trusted sources
Computer protection, which is no less important than protecting your home, is quite an easy task. All it takes is staying equipped with the essential information and the proper antivirus software, both of which you can find on Top 5 Antivirus Software.