Types of Computer Viruses

Published on: Jan 01 2011 by Shenron

For most of the people, computer virus is a program that brings about damage to their system or makes their system crash. Generally, ‘Malicious code’ is the right term used to refer to these programs and computer virus is a type of one such malicious code. Worms and Trojans are relatively different from computer viruses which are more destructive. However, these destructive worms and Trojans are grouped under Internet types of viruses. It was back in 90s when different types of computer viruses had made their mark ton the PCs.

The first or earliest virus made its impact a lot because there were no antivirus programs available at that time. Most of the antivirus present today are the product of devious and evil minds, when they saw that the antivirus software are now able to disinfect and remove the different types of computer virus, they devised new methods and ways and introduced worms and Trojans.

We have nowadays six broad categories or types of computer viruses given below:

  • Boot Sector Virus
  • File Infection Virus
  • Multipartite Virus
  • Network Virus
  • E-mail Virus
  • Macro Virus

Boot Sector Viruses

Boot sector viruses directly attack the boot sector of the hard drive and infect the vital component of the boot process. The boot sector of any hard drive holds some vital information that controls the hard drive and some part of the operating system. The aim of such viruses is to load successfully into the system memory while the boot process begins.

Boot sector viruses don’t affect your data rather they go after the drive itself on which the virus is saved. Previously, when floppy drives were excessively used, virus spread too quickly from one computer to another through the floppy disks, but since the advent of CDs and DVDs which are not infected by viruses, it becomes impossible to infect the programs that they carry. Another major reason behind this virus has become less common is the stand guard of operating systems over the boot sector which makes it almost impossible for the virus to infect the boot sector.

File Virus

File virus is a type of virus coded in a special way that it attaches itself to the exe files, compressed files such as zip files, and driver files. As soon as the program is started or the file it is attached to is opened, it sets into action. From there it keeps spreading to other files and programs until it starts along its intended mission for which it is codified. If you see closely, these viruses follows the two prong approach that is, first they duplicate themselves and then start its intended mission. They go through the computer program until they find the program for which they are written and when the program is run, these viruses activate. These viruses have the tendency to spread and infect the whole system or any other computer attached to the original system.

They viruses contain some special codes related to the certain programs or events. When those programs are events are initiated, these codes are activated. These events can be a date or any other trigger event easily defined on any of the computer system.

Multipartite Viruses

Multipartite virus is a term used to refer to the types of computer viruses which are both a file virus and a boot sector virus. These types of viruses spread through different kind of media. Once embedded in the system memory, these viruses make its way to the hard drive and eventually infect the boot sector. For boot sector these viruses spread to the executable files and finally infect the whole system.

Although, this types of computer viruses has have past their prime time for one or another reasons, these viruses were accountable for so many system crashes in the past because of their dual characteristics, i.e. of file virus and of boot sector virus.

Network Viruses

Network viruses are made particularly for networks. This virus spreads rapidly through the local area network and eventually across the Internet, but in majority of cases this virus spreads within the shared resources such as folder and drives. After getting through a computer protection system, this virus looks for vulnerable computers in the network and infect that computer in the same manner and this process keeps on going until the virus is able to find other vulnerable computers.

E-Mail Viruses

E-mail virus is a type of computer virus that is known as a macro virus. The e-mail virus is capable of spreading itself by chasing after the other contacts in an e-mail address book by send itself on its own to those contacts hoping that they will also activate it. So, we can say that this virus has a great tendency to spread itself and at times it is activated even by viewing it in the mail client. An apt example of an e-mail virus is that of ILOVEYOU virus which was a very destructive virus cause damaged all over the world. This is why it is recommended to the users that not to open the unknown mails and the junk folder is introduced by major companies.

Macro Viruses

Macro viruses are the most common form of computer viruses which infect the files that use macros in the program. For instance, the most apt example of the program that uses macros is Microsoft Office where the files created in Word document, Excel spreadsheets, Access databases, PowerPoint presentations. Some of the other files from AmiPro, Coral Draw and so on can also be infected by macro viruses.

Macro viruses are so programmed that they use language according to the application, i.e. the language that an application understands and not the language of the operating system. This shows that these viruses aim more to the applications that they are intended to make for than the operating system and this property make them harmful for all the operating systems like Mac, Windows or Linux that supports these applications. Macro viruses were introduced in 1995 and that first virus infected the Microsoft Word file, but since then they have moved to other programs and are severe in nature. Macro viruses are found in large numbers, as the macro language is becoming more and more powerful, the macro viruses has also become a crucial type of computer viruses.

It is important to remain watchful and careful about these computer viruses as they can harm your system severely. You can lose your important data due to these viruses. Take every single precaution and be very preventive while opening the dubious files.

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