Introduction to Computer Virus/ Malware
The term "Computer Virus" is sometimes used as a catch-all phrase to include all types of malware, including viruses. The expression, Malware is a general term used by computer professionals to mean a variety of forms of hostile, intrusive, or annoying software or program code. Malware, short for malicious software, is software designed to infiltrate a computer system without the owner's informed consent. Malware includes Computer Viruses, Worms, Trojan Horses, Spyware, Rootkits and other malicious and unwanted software. The term "Virus" is also commonly but erroneously used to refer to other types of malware.
On March 29, 2010, Symantec Corporation, producer of Norton Security Products, named Shaoxing, China as the World's Malware capital.
Viruses are sometimes confused with worms and Trojan horses, which are technically different. A worm can exploit security vulnerabilities to spread itself automatically to other computers through networks, while a Trojan horse is a program that appears harmless but hides malicious functions. Worms and Trojan horses, like viruses, may harm a computer system's data or performance. Viruses can increase their chances of spreading to other computers by infecting files on a network file system or a file system that is accessed by another computer.
A brief history of Virus
Traditional computer viruses were first widely seen in the late 1980s, and they came about because of several factors. The first factor was the spread of personal computers (PCs). Prior to the 1980s, home computers were nearly non-existent or they were toys. Real computers were rare, and they were locked away for use by "experts." During the 1980s, real computers started to spread to businesses and homes because of the popularity of the IBM PC (released in 1982) and the Apple Macintosh (released in 1984). By the late 1980s, PCs were widespread in businesses, homes and college campuses. The second factor was the use of computer bulletin boards. People could dial up a bulletin board with a modem and download programs of all types. Games were extremely popular, and so were simple word processors, spread sheets and other productivity software. Bulletin boards led to the precursor of the virus known as the Trojan horse. When we run the program, however, it does something unethical like erasing the disk. Trojan horses only hit a small number of people because they are quickly discovered, the infected programs are removed and word of the danger spreads among users. The third factor that led to the creation of viruses was the floppy disk. In the 1980s, programs were small, and we could fit the entire operating system, a few programs and some documents onto a floppy disk or two. Many computers did not have hard disks, so when we turned on our machine it would load the operating system and everything else from the floppy disk. Virus authors took advantage of this to create the first self-replicating programs.
Early viruses were pieces of code attached to a common program like a popular game or a popular word processor. A person might download an infected game from a bulletin board and run it. A virus like this is a small piece of code embedded in a larger, legitimate program. When the user runs the legitimate program, the virus loads itself into memory¬ and looks around to see if it can find any other programs on the disk. If it can find one, it modifies the program to add the virus's code into the program. Then the virus launches the "real program." The user really has no way to know that the virus ever ran. Unfortunately, the virus has now reproduced itself, so two programs are infected. The next time the user launches either of those programs, they infect other programs, and the cycle continues.
Types of Malwares
A Trojan horse, or Trojan, is malware that appears to perform a desirable function for the...
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