Computer Viruses In Todays Us Essay Research

Computer Viruses In Todays Us Essay, Research Paper

Table Of Contents

Introduction

What is a computer Virus

How a Virus Infects

History Of Viruses .

Virus Types …

File Virus ..

Boot Virus

Multi-Partite Virus

Polymorphic Virus

Virus Prevention

Rule 1

Rule 2

Rule 3

Rule 4

Virus Statistics .

Trojans .

Worms .

Conclusion ..

Diagrams

Chris Ruci

ITM 280

Dr. Jeffries

14 Dec 2000

Computer Viruses

Introduction

If you buy a new computer these days, it’s likely to be shipped with an anti-virus package. This fact, more than anything else, should convince us of how widespread viruses have become and how much the computer industry has come to accept their inevitability. Just like its biological reference, computer virus acts like a biological virus, in which it first is infected into the body and then spread. Quite simply, viruses are a fact of computing life.

What is a Computer Virus.

To be defined as a virus, a program must:

+ Replicate itself in order to carry out a mission

+ Be dependant on a host to carry out the mission

+ Create damage to the computer system infected .

A computer virus is a piece of software that has been written to surreptitiously enter your computer system and “infect” your files. Some viruses are benign and won’t harm your system, while others are destructive and can damage or destroy your data.

Typically a computer virus will replicate itself and try to infect as many files and systems as possible. If your system is infected, when you save a file to a disk you will probably infect the disk, and in turn whoever uses that disk will infect their system. As you can see, it’s a vicious cycle, not unlike the viruses that plague us humans (Stewart).

New computer viruses are being written all the time, and it’s important to understand how your system can be exposed to them, and what you can do to protect your computer.

How a Virus Infects

Viruses work in different ways, but there is a basic process. First, the virus appears on your system. It usually enters as part of an infected program file (COM, EXE, or boot sector). In the past viruses traveled almost exclusively through the distribution of infected floppy disks. Today, viruses are frequently downloaded from networks (including the Internet) as part of larger downloads, such as part of the setup files for a trial program, a macro for a specific program, or an attachment on an e-mail message. (Randall)

The e-mail message itself cannot be a virus. A virus is a program, and it must be run to become active. A virus delivered as an e-mail attachment does nothing until you run it. You run this kind of virus by launching the attachment, usually by double-clicking on it. One way to help protect you from this kind of virus is simply never to open attachments that are executable files (EXE or COM) or data files for programs, such as office suites, that provide macro-writing features. A graphics, sound, or other data file is safe (Randall).

A virus starts its life on your PC. It is hidden within another program or file and launches with that file. In an infected executable file, the virus has essentially modified the original program to point to the virus code and launch that code along with its own code. Typically, it jumps to the virus code, executes that code, and then jumps back to the original code. At this point the virus is active, and your system is infected.

Once active, the virus either does its work immediately if it is a direct-action virus, or sits in the background as a memory-resident program, using the TSR (terminate and stay resident) procedure allowed by the operating system. Most are of this second type and are called resident viruses (SARC 1). Given the vast range of activities allowed by TSR programs, everything from launching programs to backing up files and watching for keyboard or mouse activity (and much more), a resident virus can be programmed to do pretty much anything the operating system can do (SARC 1). Using a bomb, it can wait for events to trigger it, and then go to work on your system. One of the things it can do is scan your disk or (more significantly) your networked disks for other running (or executable) programs, then copy itself to those programs to infect them as well.

History Of Viruses

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. Prior to the 1980s, home computers were non-existent or they were toys. Real computers were rare and experts locked them away for use. 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 (Slade).

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, spreadsheets, etc. Bu

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