Computer Virus – Types of computer virus – Symptoms of computer virus

Computer Virus

You will learn about

  • Computer Virus
  • Types of Virus
  • Virus Symptoms
  • Ways to Prevent Virus Infection
  •  Antivirus Software

The virus

Nowadays, computers and the data stored in them have become vital to any organisation. If any problem occurs with them, the entire business may suffer.

What is the definition of a computer virus

A computer virus is defined as a program or a collection of programs which can disrupt the normal operation of a computer. A virus can infect or even destroy data. A virus can enter a computer without any knowledge or permission of the user.

The full form of VIRUS is Vital Information Resources Under Seize. If the virus spreads in the computer system, the various computer resources like memory, data, programs etc. also get harmed.

Virus programs replicate themselves in the computer system and they keep expanding their reach by infecting more and more computer files. This can lead to destruction of data and loss of speed.

Virus programs make the computer do undesired and unscheduled jobs. Viruses can enter the computer system via storage devices like CD, pen drives etc. that may be infected. They can also enter the system while surf on the Internet.

The viruses are secretly hidden so that they cannot be easily detected. Virus programs can stay inactive and undetected for a long period of time while waiting for an event to trigger them.

But there are also some viruses which are completely harmless. They usually display simple message. But most of the viruses are harmful. Viruses are mostly written by destructive sources who want to access someone’s confidential data.

Spyware, Worms and Trojan Horses are some terms that are related to virus programs but they are actually different from the virus programs.

WORM: It is a type of virus that copies and multiplies itself with the help of security flaws and computer networks. They have the tendency to overload the network resources that can slow down the data transmission speed because they consume a lot of system memory or network bandwidth.

TROJAN HORSE: It is type of virus that acts as a useful application but can do something very destructive. It can erase a disk. It does not replicate on its own. It spreads only when it gets copied to another system.

MALWARE: It is made up of two words Malicious and Software. It is software which will enter into a computer system and cause destruction without the user knowing about it. It may be a worm, virus, spyware or Trojan Horse. They disrupt the normal operation of a computer as well as steal important data.

SPYWARE: It is a type of malware which gets installed on computers and then collects data about users without their permission. These programs silently monitor the user’s computing. They can gather a lot of user’s personal information like visited web pages, surfing habits on internet and then transfers this information to someone else. They can also alter the computer settings which can slow down the connection speed and also harm other programs. Spywares can gather data about e-mail addresses, passwords etc.

More to know

First computer virus

The first computer Virus was a boot sector virus and it was known as Brain. It was released in 1987 by the Farooq ALVI Brothers in Lahore, Pakistan.

Types of computer virus

Types of computer virus
Types of computer virus

Viruses can be classified into the types given below based on their infection targets:

  1.  Boot Viruses: These are the type of viruses that can infect the boot record or master boot record. They have the capability to replace the boot record that loads the Operating System in the memory of the computer, by copying it somewhere else. These types of viruses are usually active when you boot your computer system. Stoned Virus, Disk Killer are some examples.
  2.  Macro Viruses: They make use of another application’s macro language for distributing themselves. They can infect/harm documents like MS Word or MS Excel and can make a sequence of actions to be triggered automatically, when an application is started. They can easily spread through discs, e-mail attachments, networks etc. DMV, Concept are some of the examples.

  3.  Program File Viruses: They usually harm the executable files and programs like those which have an extension – .co, .ovl, .exe, .sys etc. they get loaded into the computer memory at the time of execution. The virus gets active in the memory by self-replicating and infecting the files on disk. Sunday, Cascade etc. are some Examples.

10 types of computer viruses

1. Boot Sector Virus: Boot Sector Virus is in the boot sector of hard disk or floppy disk. Such viruses come into the system by removable media. When we turn on the computer, then this virus hinders the operating system to load. To remove this virus, a computer format has to be done.

2. Stealth Virus: Secret Virus As the name suggests, this virus hides its identity from the user by entering the computer. This virus tries to hide itself from being caught through anti virus. Therefore, it harms the computer by entering the computer with a different name every time.

3. Macro Virus: files Macro Virus 46 Microsoft office if word, document, spreadsheet, powerpoint harms, it also slows down their speed.

4. Direct Action Virus: Direct Action Virus It is also called Non Resident Virus (Non-Resident Virus). Once this virus is installed, it remains hidden in the computer’s memory. This virus is in the hard drive root directory. These viruses are associated with the files they infect.

5. Polymorphic Virus: Mostly this virus is used by cybercriminals. Every time this virus damages the system through different means, it is very difficult to identify such virus. Polymorphic virus is scanned using brute force program.

6. Resident Virus: Resident Virus It affects them by entering the RAM memory of the computer. Resident viruses are made in many different ways, in which some viruses work very slowly, some viruses work very fast and some secretly.
Many problems arise due to the spread of this virus in the system, such as operating the system, system shutdown, and copy-pasting some data, etc. Sometimes this virus is also associated with anti virus.

7. Partition Table Virus Partition table virus reduces RAM capacity. This virus does not harm the data of the computer, but this virus damages the partition table of the hard disk. And infects the master boot record of the hard disk.

8. Browser Highjack Virus: Today the Internet is being used a lot and this is mostly the reason for spreading virus in the system. We open any type of website, file, play online game, watch online movie, due to this there is more possibility of virus getting in our device. Due to this, our system also starts running slow, if this virus comes in the system, then it damages the data, files. Such viruses spread very easily in our system through the internet.

9. File Infectors Virus: Today, most of the File Infectors in the system have this virus because this virus directly affects the running file and damages the data, file. These viruses are associated with .bin files, exe files

10. Overwrite Virus:

To remove the overwritten virus from the system, only those files have to be deleted which is infected _files, it causes a lot of damage. These viruses enter the system through e-mail, it is very difficult to identify such viruses.

More to know

The Creeper Virus was detected first on the ARPANET in the early 1970s.

Computer virus symptoms

 Computer virus symptoms
Computer virus symptoms

Preventing computer virus infection

Preventing computer virus infection (1)
Preventing computer virus infection (1)

Antivirus Software 

They are computer programs that are developed for identifying, preventing or removing viruses from a computer. They can perform the following tasks in a computer:

  • Scan all the computer files to find viruses.
  • Try to recognise any kind of suspicious behaviour from any computer program which may be an indication of an infection.

We should keep our systems updated with the latest versions of antivirus software so that they can detect the new types of virus programs. We can download the latest versions from their web sites cites themselves, for most of the Antivirus softwares. Some of the well known antivirus softwares are Norton Antivirus, McAfee Virus Scan, AVG Antivirus, PC- Cilin etc.   

Quick Brush Up

A computer virus is defined as a program or a collection of programs which can disrupt the normal operation of a computer.

The full form of VIRUS is Vital Information Resources Under Seize.

The viruses are secretly hidden so that they cannot be easily detected.

A Worm is a type of virus that copies and multiplies itself with the help of security flaws and computer networks.

Trojan Horse is a type of virus that acts as a useful application but can so something very destructive.

Malware is a software which will enter into a computer system and cause destruction without the user knowing about it.

Spyware is a type of malware which gets installed on computers and then collects data about users without their permission.

Computer Virus

Read also 

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