computer virus



Computer Virus

Melissa, Bubbleboy, WM Concept, Stoned, Michelangelo, …, the list goes on and on. You might ask what do all these names have in common. The similarity between them is that they can cause damage to your computer. In short they are simply known as “computer viruses”. For most users, the term “computer virus” is a synonym of the worst nightmares that can happen on heir system. A computer virus is an illegal and potentially damaging computer program designed to infect other software by attaching itself to any software it contacts. In many cases, virus programs are designed to damage computer systems maliciously by destroying or corrupting data. The viruses can do one or all of the following things: Take control of your computer without your knowledge, cause your computer to act strangely, and cause damage to some files.
An infected file that is loaded into memory and executed causes a computer to catch a virus. In a computer the virus first infects the computer’s memory. The contact can take place by using a virus infected floppy disk, or by opening a virus infected e-mail attachment, or any other method where the virus comes into contact with the computer’s memory to infect the computer. Also, if the infected software is transferred to or accessed by another computer system, the virus spreads to the other system. If an infected file is not opened, the virus cannot infect the computer.
There are millions and millions of viruses out in cyberspace, and that list continues to grow weekly. However, all these viruses are only one of the 3 types of viruses. The three types of viruses are a boot sector virus, file virus, and Trojan horse virus.
The boot sector virus hide on the sector of the disk known as the boot or partition table of a disk. Affecting the computer system during the start-up process. These viruses are difficult to deal with because they read during the start-up process even before the system is able to load its anti-virus software to detect the virus. It will take control after which it will coy itself into RAM so that when other disks are called on for service, the virus will transfer to their boot sectors. One of the most wide spread virus is the application or fie virus. This attaches to executable .exe or .com files. This type of virus takes control after the infected file has been ran or executed. When the infected file is running, the virus is loaded into the computer’s memory where it can infect every program run on the computer till shut down. Some just replicate themselves while others destroy the program being used. Unlike most viruses the stealth virus attempts to hide its presence. Some techniques of hiding include: change in date and time, and hiding the increase in file size. Some prevent anti-virus software for reading the file where the virus is located also encrypting the virus code with encryption techniques aids in the stealth. Macro viruses which attaches to a word-processing or spreadsheet file as a macro. It can start programs that may be able to delete the users files on the computers hard drive and infect all other document spreading its self. Looking at the above we can see the damage that can occur when viruses are unprecedented. The amount of lost processing time and man-hours to correct the problems associated with them and lead to large amounts of money and equipment. When the infected boot program executes, the virus is loaded into the computer’s memory. Once a virus is in the memory, it can spread to any floppy disk inserted in to the computer. A file virus inserts virus codes into program files. The virus then spreads to any program that accesses the infected file. A Trojan horse virus (named after the Greek myth) hides within or is designed to look like a legitimate program.
Some viruses interrupt processing by freeing a computer system temporarily and then displaying sounds or messages. Other viruses contain time bombs or logic bombs. A time bomb is a program that performs an activity when a certain action occurs, such as an employee being terminated. A worm, which is similar to a virus, copies itself repeatedly until no memory