A computer virus is a computer program that can copy itself and infect a computer without permission or knowledge of the user. However, the term "virus" is commonly used, albeit erroneously, to refer to many different types of malware programs. The original virus may modify the copies, or the copies may modify themselves, as occurs in a metamorphic virus. A virus can only spread from one computer to another when its host is taken to the uninfected computer, for instance by a user sending it over a network or the Internet, or by carrying it on a removable medium such as a floppy disk, CD, or USB drive. Additionally, viruses can spread to other computers by infecting files on a network file system or a file system that is accessed by another computer. Viruses are sometimes confused with computer worms and Trojan horses. A worm can spread itself to other computers without needing to be transferred as part of a host, and a Trojan horse is a file that appears harmless until executed.
How a Computer Virus Works?
The mechanism of a computer virus can undoubtedly be compared with working of a biological virus. Both of them more or less work in a similar way but follow different analogy.Unlike the computer virus, a biological virus is a fragment of genetic code, DNA, which breathes inside a human body and infects living cell by spreading rogue DNA into the cell environment. The viral DNA keeps replicating itself in the cell’s existing machinery.
Likewise, the computer virus seeks for a host i.e. any program or document to infect a machine and replicates itself each time a user opens the program. When the user opens an infected program, the virus loads itself into the computer’s memory and searches for another host to reproduce, thereby creating a vicious circle for itself.
Several viruses were originally designed to infect the boot sector, the part of the operating system that loads at the time you switch on your computer. The boot sector helps the computer in loading the operating system. By putting code in the boot sector, the virus is active every time the user switches on the computer.
General modes of computer virus transmission are infected floppy discs or documents uploaded to bulletin boards. All viruses have a sole aim to ruin computers’ functionality which is the main part of the attack phase. When the virus is being activated, a small program is opened to perform a task. It can be an attractive message on the user’s screen or it may attempt at deleting all the data present on your hard disk drive.
Immediate computer virus repair is must to avoid damage to computers. There are some terrible viruses that are always ready to scour the network’s functionality, thereby making it crucial to avail virus support. With technical support services have become the next big thing and arrival of names like IBM, Dell, iYogi, and Circuit City, the task of removing computer viruses can be done in no time.
Many personal computers are now connected to the Internet and to local area networks, facilitating the spread of malicious code. Today's viruses may also take advantage of network services such as the World Wide Web, e-mail, and file sharing systems to spread, blurring the line between viruses and worms. Furthermore, some sources use an alternative terminology in which a virus is any form of self-replicating malware.
Some viruses are programmed to damage the computer by damaging programs, deleting files, or reformatting the hard disk. Others are not designed to do any damage, but simply replicate themselves and perhaps make their presence known by presenting text, video, or audio messages. Even these benign viruses can create problems for the computer user. They typically take up computer memory used by legitimate programs. As a result, they often cause erratic behavior and can result in system crashes. In addition, many viruses are bug-ridden, and these bugs may lead to system crashes and data loss.
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