Types Of Computer Virus

Types Of Computer Virus

Computer virus is a program or piece of code that is loaded onto your computer without your knowledge and runs against your wishes. Viruses can also replicate themselves. All computer viruses are man-made. A simple virus that can make a copy of itself over and over again is relatively easy to produce. Even such a simple virus is dangerous because it will quickly use all available memory and bring the system to a halt. An even more dangerous type of virus is one capable of transmitting itself across networks and bypassing security systems. Since 1987, when a virus infected ARPNET, a large network used by the Defense Department and many universities, many antivirus programs have become available. These programs periodically check your computer system fro the best-known types of viruses.

Computer Virus And Ways They Spread
Computer Virus And Ways They Spread

Computer viruses are malicious software programs that damage computer program entering into the computer without the permission of the users, and also run against the wishes of the users. They are replicated by themselves. Viruses are so dangerous and malicious that they can be automatically copied and pasted from memory to memory over and over; the transmitting power is too much quick from network to network that can simply hang smoothly running computer,  sometimes damage the important programs of the computer. Viruses are very dangerous program can go on their activities automatically and can do a great loss of the users. It is quite impossible to give the proper information about the types of viruses. The types of viruses are changing day by day. Therefore on the basis of their origin, hiding, damaging types, operating system etc their types are as follows:

Boot Viruses
Boot sector virus is a type of virus that infects the section of a disk that is first read by the computer. This type of virus infects the boot or master section of any disks that it comes in contact with. These viruses replace the boot recorded and move it to a different part of the hard disk, or simply overwrite it. Once you start your operating system, it loads into memory, along with the virus. Once the virus is in the memory, it is free to do whatever it is programmed to do. To avoid loading the boot record viruses into memory, you must boot your operating system from another source.

Program Viruses
Program Viruses is a type of virus that infects only executable files. Once executed, these programs load into memory, along with the virus contained within them. Once in the memory, the scenario repeats – the virus  is free to act and infect other files or simply deliver its payload. These viruses are friendlier than boot viruses and can be removed easily.

Polymorphic Viruses
Polymorphic virus is one that creates copies of itself, with variations in each copy to fool a virus detection program and user. The variations are typically different encryption methods in the virus file copies, Which makes it more difficult for a virus detection program to detect and remove a polymorphic virus from a computer.
Polymorphic infections are difficult for virus detection programs to clean because one polymorphic virus could have hundreds or thousands of variants. Developers that design the detection programs have to write extra lines of code in order to make the programs better at detecting and cleansing polymorphic infections, although antivirus programs with heuristic do have a better time at detecting these types of viruses.

Parasitic Viruses
When you start a program infected with a parasitic virus, the virus code is run. To hide itself, the virus then passes control back to the original program. The operating system on your computer sees the virus as part of the program you were trying to run and gives it the same rights. These rights allow the virus to copy itself, install itself in memory or make changes on your computer. Parasitic viruses appeared early in virus history and then became quite rare.

Stealth Viruses
Stealth virus is a hidden computer virus that attacks operating system processes and averts  typical anti-virus or anti-malware scans. Stealth viruses hide in files, partitions and boot sectors and are adept at deliberately avoiding detection. Stealth virus eradication requires advanced anti-virus software or a clean system reboot. Stealth viruses hide altered computer data and other harmful control functions in system memory and self copy to undetectable computer areas, effectively tricking anti-virus software. In order to avoid detection, stealth viruses also self modify in the following ways:

  • Code Modification: The stealth virus changes the code and virus signature of each infected files.
  • Encryption: The stealth virus encrypts data via simple encryption and uses a different encryption key for each infected file.

Multipartite Virus
Multipartite virus is a fast moving virus that uses file infectors or boot infectors to attack the boot sector and executable files simultaneously. Most viruses either affects the boot sector, the system or the program files. The multipartite virus can affect both the boot sector and the program files at the same time, thus causing more damage than any other kind of virus. When the boot sector virus because it latches on to the hard drive that contains the data that is needed to start the computer. Once the virus has been triggered, destructive payloads are launched throughout the program files.

E-Mail Virus
E-Mail virus is computer code sent to you as an e-mail note attachment which if activated, will cause some unexpected and usually harmful effect, such as destroying certain files on your hard disk and causing the attachment to be remailed to everyone in your address book. The best two defenses against e-mail viruses for the individual users are:

  1. A policy o never opening an e-mail attachments unless you know who sent it and what the attachment contains, and
  2. Installing and using anti-virus software to scan any attachment before you open it.
    Business firewall servers also attempt, but not always successfully, to filter out e-mail that may carry a virus attachment.

The Melissa virus macro virus and the ILOVEYOU virus are among the most famous e-mail viruses.

Software Measures To Protect The Computer System

Computer software, or simply software, also known as computer programs, is the non-tangible component of computers. Software security is an idea implemented to protect software against malicious attack and other hacker risks so that the software continues to function correctly under such potential risks. Security is necessary to provide integrity, authentication and availability. Some of the security measures for the data, information and software are data backup, password protection, virus scanning, defragmentation and scanning a disk.

Checkout: Best 10 Anti-Virus Software

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