Computer Viruses Essay Research Paper Julio Contreras

Computer Viruses Essay, Research Paper

Julio Contreras

What is a computer virus.

Sometimes the term “virus” is misused. Some people tend to use the word “virus” to refer to anything undesirable that can happen to a computer, but this is not completely accurate. Viruses are short programs that are not accidental. Someone, somewhere, has purposely designed them, usually with malicious intent. It is usually copied and passed along many times before it reveals its existence. “A virus is any program that reproduces itself by using the resources of your computer without your knowledge or consent.”

A virus just copies itself and spreads. A virus cannot move by itself, it must attach itself to another program. Viruses may be written to multiply, to damage other programs, or to alter data.

There are many different kinds of viruses. Viruses come in a wide variety. They are often small and well hidden, therefore difficult to find. Some are slow while others are fast. Some take days, weeks, months or years before they start damaging a computer. They may be benign and result only in amusement or mere annoyance, or they can be malignant and malicious.

Before we start talking about the different characteristics of a virus, we should first see how a virus works.

How does a virus work.

The first step of a virus is to initialize the computer. It remains hidden and tries to gain control from the operating system. The next step is for the virus to set up virus processing and modifies the system to support virus control. Then the virus wants to find available hosts. Its job is to seek new receptive hosts and determine if they are available for infection. They want to infect as many systems as possible. They infect the system by attaching themselves to the host. They moderate their infection activities to reduce the risk of being found. This is when a virus officially begins its destruction of a system. A virus wants to determine if it is time to activate. This depends on a number of things. It needs to know the preset number of infections, the elapse time in the system, the preset data or time, and other external events, which have occurred. Depending on these factors the virus determines if it should be destructive at this time or if it should wait. At the end the computer is usually unaware of the infection.

Basically all a virus does is live in a host program. Each time the host program is executed, so is the virus. When the virus is executed, it seeks at least one other program to which it can copy itself. This is why a virus is constantly spreading.

What are some intrusive programs.

Viruses are not the only programs that can disrupt a computer system. Sometimes other programs get confused with viruses. Some of these programs are Trojan Horses, Worms and Logic or Time Bombs.

A Trojan Horse is a program that does something more than the user was expecting, where this extra something is damaging. It is not a virus because it does not reproduce itself. It is designed to look innocent but when they are run it causes harmful effects. These programs were named after the Trojan Horse used by the Greeks at the siege of Troy. Greek soldiers hid inside a wooden horse and when the Trojans took this horse inside the city of Troy, the Greeks jumped out and attacked. This is the same way a Trojan horse in a program works inside the computer. Trojans hide with in a program that appears legitimate. When you load this program…TROUBLE BEGINS.

Worms are also programs that alter or destroy data. Worms are easier to deal with than viruses once they are found. The reason being that unlike viruses, worms do not duplicate themselves. It is a program that is designed to invade a workstation. Once it invades this workstation, it then disables it.

Logic or Time Bombs are like Trojan Horses. They are similar in their programming and ability to damage data. However, the differences are in the design. It is designed with a built-in timing device so it will go off at a certain time. They can be detected before they are activated if you use a good scanning program regularly.

Where do viruses reside.

The areas where they initially infect can classify computer viruses. There are two general categories: File infections and System or Boot-Record infections.

File infections (or program viruses) attach themselves to ordinary program files. These are usually .COM or .EXE files. File infections can be either Direct Action Viruses or Resident Viruses. Direct Action Viruses have one major concern. Their job is to search for other programs to infect each time it is executed. Resident Viruses hide themselves in memory. Then when an infected program is executed it infects other programs.

System or Boot-Record infections also called Boot Sector Viruses, deals with the computer as it is being loaded. The boot segment contains instructions for the computer. It is the first part of the system to be activated when a computer is turned on. It contains small programs necessary to start (boot up) the system. It is a hidden part of the hard or floppy disk. Boot viruses infect code found on a disk and gains control of the system. Boot viruses monitor all of the processes in a computer and modify them. It implements the self-defense mechanism. Attempts to erase, replace, or modify the boot

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