What is Computer Virus (Attack, Spread & Protection)

A computer virus has very similar characteristics to that of the flu virus. Both need a host to do their work, both spread from one host to another and both of them have replicating abilities. In one case, humans act as hosts while in the other computer programs and files act as hosts.

If we get to its technical definition then it is a malicious program that replicates itself when executed and inserts its own code to change the computer program. These new programs when executed, do not perform as expected which is said to be affected by computer viruses. During this process, the virus causes unexpected damage to the system by harming the system software by corrupting or destroying files and data. These viruses are the root causes of all the major computer scams happening around the world.

How does a Computer Virus attack?

There are many ways by which viruses can spread like when the user opens a corrupted email attachment, runs an executable file, has visited an infected website, and views an infected advertisement which is generally called malvertising. Viruses can also spread through the use of infected removable devices like USBs. 

Once the virus is injected, it can affect other system software of the device, It can do changes to core functions or resources by modifying or disabling them, or can copy, edit, encrypt or delete the data, even damaging the hard disk. However when one computer gets infected by the virus,  then it can easily infect other computers on the same network. Devastating and irritating things a virus can do include password stealing, corrupting files, logging keystrokes, and marking your email contacts as spam.

How do computer viruses spread?

Virus propagation is a very disgusting property of a computer virus in which the virus spreads from one system to another system when the user,  either intentionally or accidentally takes some action that facilitates spreading. There are many different techniques by which viruses can propagate. They can propagate through emails, can be attached to a file that users download from the net, or it can spread through removable devices. Viruses can spread by getting attached to socially sharable content like images, videos, audio files, GIFs, etc.

In order to avoid contact with viruses, we need to be more careful while surfing the web, downloading files, opening attachments, etc. Do not download or open a file if you doubt its safety. 

Sign of Computer Virus?

A variety of symptoms can be seen if attacked by a virus. Some are:

• Speed of the system: In case your computer gets infected by the virus it will reduce the performance of the computer. So, if you see a sudden change in the processing speed of the computer, it could be an alarming signal.
• Frequent pop-up windows: Pop-ups can encourage you to open an unusual site that may not be safe. One can get frequent pop-ups up on the screen which might be virus-affected and can even cause more harm.
• Changes to your homepage: You will see sudden changes on your homepage, and it may happen that you will be unable to change it.
• Mass emails being sent from your account: You can notice that anonymous emails will be sent from your account without your acknowledgment
• Frequent crashes: A virus can cause major damage to your hard disk. It may cause your device to freeze or crash.
• Unusual activities happen: Unusual activities like password changes can occur which can prevent you from logging in.

How to protect against a computer virus?

There are certain ways by which we can protect our computers from being infected with viruses. They are:

• Use trusted anti-virus software that will give you a warning if any uncommon activity happens.
• Totally avoid clicking on any pop-up ads.
• Before opening any email attachments, scan them.
• Scan downloaded files using a file-sharing program.
• Use the internet browser’s privacy settings-Modern browsers have privacy settings from which you can control what sites can see or do. Because there are some websites that use your personal information for their use such as for theft, fake advertisement, and fraud. By enabling privacy settings you can protect your system from viruses.
• Check Windows SmartScreen notifications- Avoid using or downloading unrecognized apps because it is unsafe for the system they might have a virus so it will enter into your computer. Windows SmartScreen notification will help you to identify the reputation of apps and when you download any unrecognized or not well-known app from the internet it will warn you to use it because it might be malicious.
• Make sure Windows is up to date- From time to time Microsoft keeps adding some new security updates it will protect your PC from malicious activities. You can prevent viruses and malware attacks by updating Windows.

Types of computer viruses

There are different types of computer viruses. A few of them are mentioned below:

1. Boost  sector virus

It affects the boot sector of the floppy disk or hard disk. The boot sector generally contains the files which are required while starting the operating system of your computer. This virus generally controls the boot or start of our computer.

2. Web scripting virus

Codes of web pages and web browsers are exploited by this virus. If we access such pages or browsers, it can affect our computer.

3. Browser hijacker

As the name suggests, this type of virus hijacks certain features of web browser and direct us to unwanted pages.

4. Resident virus

This virus saves itself in the memory of the computer system and then infects other files and programs. This can execute at any time whenever the OS loads.

5. Direct action virus

Direct action virus gets attached to a .exe or .com file and enters the computer system during the execution of these files.

6. Polymorphic virus

These viruses spread through spam and infected websites and are very hard to detect. These viruses change their code every time execution takes place.

7. File infector virus

The main resource for the spread of these viruses are games and word processors. As the name suggests, the first effect is a single file and it later spread to all the existing files.

8. Multipartite virus

Multipartite viruses can affect both, the boot system and executable files of a system that is already infected by a virus. There is a risk of a cyber threat if you get affected by a multipartite virus.

9. Macro virus 

These are viruses that are written in the same macro language as used for software applications. The main source for the spread of these are emails and infected documents attached to them.

How to remove a computer virus?

Although the process will depend on the Windows version used, some general steps are:

• First of all, enter safe mode.
• In safe mode, use the disc cleanup tool to delete all the temporary files.
• Download on-demand and real-time virus scanners.
• Run one followed by another, if non of them detect a virus then you need an expert to remove the virus manually.

Conclusion 

A computer virus is a malicious program that replicates itself, enters the system, corrupts the files, and does unexpected harm to the system. They could also lead to cyber threats and can cause great damage to existing files. So to avoid them, a system must have an anti-virus installed, anyone must be very careful while browsing the web, should scan all email attachments before opening them, and scan files before downloading them.