Computer Virus

“Computer Virus”

What is a Computer   Virus ?
“A Software program able of reproducing itself and usually capable of causing great harm to files or other programs on the same .”
OR  
“A   virus is a program that may disturb the normal working of a computer virus .”

How   is a Computer Virus created?
The following are the points through which the computer virus is created:
History
  * Computer viruses are created by programmers who write code that builds a program with replication and destructive abilities. They do this because they are either malicious for the sake of being destructive or are malicious and driven by corporate disruption or financial gain. Virus code is written to allow a program to hide, wait and attach itself to other files and programs. Virus creation has its roots in the Cold War era, when former computer scientists and espionage agents were suddenly out of work and began to create destructive code to be released. Early viruses were born from jilted and disgruntled employees.

Purpose
  * Viruses can destroy data. They can cause a shutdown of information technology, and they can cause loss of information. Viruses differ from worms in that worms exist solely for replication and inhibit machines due to massive resource consumption. Viruses are similar to Trojan programs in that they are both created with malicious intent. However, Trojan programs function mainly in opening up "back doors" on systems for unauthorized users.

Infection
  * Viruses enter computers through either Internet connections or virus-infected programs being loaded or run within a healthy computer. Viruses come in many designs. There are polymorphic viruses, which shift their detectable traits as they copy and infect a machine. Camouflaging viruses mask themselves, giving the appearance of standard programs. Viruses with stealth have the ability to hide from anti-virus software. A special case is the virus dropper, programs that carry viral code and...