Categories: Computer ScienceTypes

Computer Virus & Its Types

The computer is an electronic device that is present everywhere from our homes to the leading companies and organizations. Computers make our day-to-day tasks easier and faster. But sometimes, computers also encounter viruses that can access our files and compromise the security of our information. So, first of all, you need to know what is a computer virus,  how it affects & the types of computer viruses.

What is Computer Virus?

A computer virus is simply a program that spread like biological viruses and takes unexpected actions when they go into a computer. Although not all viruses are dangerous, many are written with the purpose of destroying certain types of files, applications, or operating systems.

Computer Virus

Computer Viruses like all other programs use system resources such as memory and hard disk space, and CPU power and can perform dangerous actions, such as deleting files on a disk or the entire hard disk. A virus can also allow access to the device over the network without authentication.

History Of Computer Virus

BBN Technologies engineer Robert Thomas built the first known computer virus in 1971. The first virus was the “reptile” virus, and a test program was run by Thomas-infected motherboards at ARPANET. The text message shown on the screen was: “I am a crawler: if you can catch me.”

But the original risky computer virus was possibly the first to be tracked in the history of computer viruses, the Elk Cloner. He infected Apple II operating systems with floppy disks. The message displayed on the infected Apple computers was a funny message.

The virus was developed in 1982 by Richard Screnta, a teenager. Even if computer viruses are developed as a joke, it also clarifies how to install the malware in computer memory and does not give users access to delete it.

It was Cohen who coined the term “computer virus” a year later, in 1983. The term came about when he tried to write an article entitled “Computer Viruses – Theory and Experiment” in Writes about malicious programs in it.

Sources  Of Computer Virus

Computer viruses can spread via Internet through a number of different mechanisms. The computer virus can arrive on your computer through one of the following:

Downloads: Hackers can hide viruses in applications, documents submitted through file-sharing services, add-ons, and other places that you often download.

Emails: The preferred method of cybercriminals is e-mails or emails holding malicious attachments. These attachments are typically implanted in the email as executable files such as ZIP or EXE.

Old Software: If you haven’t updated your program’s application software or operating system in a while, there are absolutely vulnerabilities in this old software that hackers can use to get viruses into your system.

Messenger Services: Viruses can also be spread via SMS or trending messaging services such as Facebook Messenger, WhatsApp, and Instagram. In these messengers, like emails, viruses become malicious links, attachments, or executable files.

Online Advertising: Viruses can also hide in online advertising such as banner advertising. This method is very dangerous hackers can hide their malicious code even on trustworthy websites such as the New York Times.

What Does a Computer Virus Do?

Computer viruses generally work in two ways. The first type begins to multiply as soon as it gets into a new computer. The second type remains dead until it arrives at the right time and starts that malicious code. In other words, the infected program must be run. Therefore, it is very vital to protect the installation of programs by installing a powerful antivirus program.

The latest computer virus has many capabilities that help bypass antivirus software and other advanced levels of cybersecurity. The main target can include stealing passwords or data, entering keys, corrupting files, and even controlling the device.

Subsequently, the latest development of polymorphic malware permits viruses to modify their code with a dynamic release. This has made virus identification very difficult.

Symptoms of Computer Virus

Computer viruses can spread during Internet downloads, email attachments, infected removable disks such as DVDs or flash drives, memory cards, malicious links on social networks, and more. If a computer is infected with a virus, it may show a variety of symptoms. Here are some general symptoms of this computer virus infection:

  • Automatically launch unknown applications
  • Exe and com files raise and increase in size
  • Pop-up windows open frequently
  • The programs we run do not run correctly and fail to continue with a few error messages that are not understandable to us
  • Changes to your browser homepage
  • Suspicious changes in folders
  • Send bulk emails repeatedly from your email account
  • Reduce system memory
  • Frequent crashes on your computer
  • Suspected CHKDSK error messages
  • Your computer slows down strangely
  • Strange activities such as changing passwords, creating unknown files, etc.

Features of Computer Virus

A program is called a virus program that has the whole following feature:

Symptoms of Computer Virus
  • Hang software that does not belong to the virus program by attaching parts of this program to other programs
  • Capable to make changes in some programs
  • Ability to detect whether the program has already changed or not
  • Prevent the further change of a program in case of changes in it due to a virus.

Modified software has features 1 to 4. If an application lacks one or more of the above features, Yes! It cannot be definitively called a virus.

Phases Of Computer Virus

The virus basically has 4 phases:

  • Sleep Phase
  • Reproductive Phase
  • Start-up Phase
  • Destruction Phase

Sleep Phase: The inventor of the virus can use the sleep phase in order to gradually get the user’s trust, as the virus does not multiply and does not damage the database.

Reproductive Phase: In the reproductive phase, it begins to appear with the launch of the program. In the process of reproduction, viruses convey their imaginary copies to other programs or stay in certain areas of the secondary storage. Then they become the original virus and continue the development process of reproduction, that is, copy new virtual copies.

Start-up Phase: The start-up phase is related to the fact that the virus occurs after a particular time, month, year, or a specified number of copies in the program.

Destruction Phase: Finally, mass damage happens during the destruction phase. At this point, the virus releases its cargo. Shipment is malicious code that damages your device.

Types Of Computer Virus

As we said, viruses are a branch of malware that can come into our computers in different ways. Here are some common types of computer viruses:

Boot Sector Virus

The boot is liable for loading your computer’s operating system during startup. As the name implies, boot sector viruses sneak into your computer’s boot sector to directly infect your system memory. These types of viruses are usually spread through hardware such as floppy disks, USB drives, and CDs. Stoner virus 2014 is one of the most dangerous types of boot sector virus.

Trojan Horses

Trojans is a senseless program that is usually spread over the Internet. Trojans install on your computer and primarily introduce themselves as a useful program, but their original function remains unknown to the user.

Secondly, they are used to disable the security of your computer. Trojans delete the data you require as well as send the data of the infected computer to the desired address. This leads to making unauthorized connections to the computer from the Internet.

Direct Action Virus

This non-resident virus is also called, installs, or hides in the computer memory. It attaches to specific types of files that become infected. This has no effect on the user experience and system performance.

Memory Resident Viruses

These viruses live in your computer’s RAM and carry out malicious behavior. Usually, another virus is used to run them. Unlike direct-acting viruses, resident viruses are installed on the computer. They stay in the computer’s memory even if the virus that helped them start is shut down.

Multipartite Virus

As files and boot space become more polluted, the power of multivariate viruses becomes massive and unpleasant. These viruses are very difficult to wipe out because they can hide parts of themselves in a file or boot space. These viruses can restart and begin multiplying even after the operating system is restarted.

Polymorphic Virus

These viruses come out in any infected file. They not only reproduce instinctively but also change their codes as they multiply. Due to the fact that they use encryption algorithms and clear their traces, it is difficult to identify such viruses.

Overwrite Virus

This type of virus deletes all infected files. The only possible removal mechanism is to delete the infected files and the end-user will have to lose all the contents. It is difficult to detect a transcription virus by spreading it via email.

Spacefiller Virus

These viruses are the most complex and difficult type of viruses for hackers. These types of viruses place themselves in empty spaces within programs. They do not show any visible signs and even show no signs of increasing volume or slowing down in their carrier program.

Macro Viruses

These types of viruses do not infect programs directly. These viruses target files generated by programs that use macro programming languages such as Excel or Word documents. Macro viruses can be spread through disks, networks, or files attached to e-mails.

The virus can only be activated when an infected file is opened. This will cause the virus to begin spreading on the computer and affects other existing files. Transferring these files to other computers or sharing the file between different devices will spread the infection to these viruses.

Armored Virus

As the name shows, it is very difficult to identify armed viruses. This means that these types of viruses are protected against possible detection and can reside on your computer and carry on causing damage. Armed with the virus, it bypasses antivirus programs by pretending to be located somewhere other than its real location.

File Infecting Viruses

These types of viruses infect executable files and run these programs and load themselves into the device memory. It automatically starts spreading itself and infecting other executable files of the system. Some types of these viruses replace the text of the executable file with the text they want.

Rootkit Viruses

Rootkit viruses are popular because of their most dangerous and skillful hiding. Rootkits are used to get your computer captured by malicious hackers. Some rootkits cannot even be detected by antivirus programs because they present themselves as operating system files. Rootkits are typically installed on your computer by Trojans.

Time or Logic Bombs

These are viruses that are triggered when a particular date or time arrives or when a specific action is taken by a user. For example, on Laughter Day (April 1) or New Year’s Eve, deleting data from your computer can give you a “gift”.

Examples Of Computer Virus

Common examples of computer viruses are as follows:

Time Bombs

Time bombs or logic bombs perform an activity on a particular date. Michelangelo is a time bomb that destroys data on the hard disk on March 6.


The worms spread from one computer to another as well as control the infected computers and attacks other networked computers.

Trojan Horse

Trojan horse contains hidden instructions and erases data or causes other damage. It does not generate copies of itself.

How To Get Rid Of A Computer Virus?

Never avoid a computer virus that resides on your system. It is possible that you will ultimately lose important files, programs, and folders. In some cases, the virus also damages the system hardware. As a result, it is vital to install effective anti-virus software on your computer to avoid such threats.

Final Words

I hope you read the article What is a computer virus? Introduce the types and their destructive effects. Still have any queries or suggestions, write us in the comments box. We will respond to you as earlier as possible. Share it with your friends if you find it informative. Keep visiting!


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