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Computer Viruses Probably one of the most misunderstood phenomenon of the computer world is the computer virus. The misconceptions and panic caused by these technological viruses are responsible for more destruction to the computer world than the viruses themselves. There is also the belief that all computer viruses cause damage to a computer, when in fact, there are many viruses used to do good when they infect a computer. Unfortunately, the public only tends to listen to those who have very little knowledge of the workings of these viruses. The press would rather tell the story of the new virus that came out that will destroy millions of hard-drives. The media does not want to listen to the actual experts who say the threat is not serious, and damage will be minimal.
There are actually just as many computer hoaxes going around as actual viruses. Due to the misinformation given to the public, those who have bought in to the story of the newest computer terror, may throw away a perfectly good computer because of a small glitch which they interpret as an infected hard-drive. The truth of viruses is easy to find, but it seems many people choose to remain blind to their actual effects. Earlier computers could run only one procedure at a time. Once engineers learned how to run programs simultaneously, procedures sometimes overstepped their assigned boundaries and damaged data in other parts of the system. This damage appeared at random memory locations.
To the engineers, this pattern resembled worm-eaten wood. So the patterns became known as wormholes, and the bugs that created them became known as worms. Eventually, one worm spread between computers on a network system. This was called the Xerox Worm, and it set the precedent for computer viruses.
Engineers began creating worms which they used to battle one another with over a network. These core wars still take place today. In 1983, a researcher performing experiments on Digital Equipment Corporation VAX systems, named Fred Cohen defined a computer virus as A program that can infect other programs by modifying them to include a version of itself. This means that basically all viruses copy themselves. They also try to escape detection by changing slightly each time they replicate or by encrypting themselves. There are two types of viruses: Research or those in the wild.
Research viruses are almost never distributed to the public and are written for research or study purposes. All viruses in the wild target Personal Computers. The viruses we worry about do more than replicate however. They contain a payload, which is a set of instructions designed to disrupt the normal function of a computer. The payload can do anything from causing a message to flash on the screen, to a complete overwrite of file allocation tables.
This causes all data on your hard drive to be lost. Some viruses are triggered by merely running the program the virus has attached itself to, while others use the internal clock of a PC to trigger the payload on a certain date. Both Research viruses and those in the wild can be defined as one of four types depending on how they spread: Boot Sector Viruses attach themselves to floppy disks then copy themselves onto the boot sector of your hard drive when you reboot your system. These can only be transmitted through a disk.
Program Viruses attach themselves to executable files belonging to other programs. This means it can infect EXE or COM files, but when the infected file is run, the virus loads onto your memory and can infect any file that your computer runs when it launches a program (e. g. : SYS, DLL, BIN, and others). Multipartite viruses infect both program files and boot sectors. Macro Viruses are basically a variation of the program viruses.
They infect templates, such as those used for office documents used to create spreadsheets or any other document. These can spread between platforms and are now becoming very widespread. Viruses normally contain different characteristics. One of these is called Memory Resident. Memory Resident viruses stay in memory where they can easily replicate themselves into boot programs. Another characteristic is called Non-Resident.
This type of virus does not stay in memory while host program is closed. Non-Resident viruses can only infect when the program is open. Stealth is the ability to hide from detection and repair. Stealth occurs in two different ways, Full: Virus redirects disk reads to avoid detection, and Size: Data is altered to hide the additional bytes of the virus. Encrypting is a technique of hiding by transformation. When encrypting, a virus code converts itself into cryptic symbols, but to spread, it must decrypt, which then can be detected.
Polymorphic viruses mutate by changing code segments to look different from one infection to another. These characteristics make viruses very difficult opponents for anti-virus software programmers. A Triggered Event is an action built into a virus that is set off by the date, a particular keyboard stroke or DOS function. This can trigger a message to flash, delete files or format the hard drive The first viruses were found in the wild in 1981 on the Apple II platform.
This was originally a harmless experiment, but it caused certain programs to abort spontaneously. In 1986 the first IBM-PC virus appeared and was called the Brain virus. Brain was a boot sector virus, although it was relatively harmless. When an attempt was made to read an infected boot sector, Brain would just show the original boot sector instead.
This means that if you look at the boot sector using DEBUG or any similar program, everything will look normal, if the virus is active in memory. This means Brain was the first stealth virus as well. Variable encryption viruses were discovered in 1989. These used encryption and various disassembly and anti-detection technology. In 1992 the Michelangelo virus was found by researchers. It was programmed to be triggered on March 6, his birthday.
The mass hysteria brought on by the media caused panic worldwide. Sales of anti-virus software went up drastically, but when the dust had cleared, only 20, 000 computers had been infected. Macro Viruses made their debut in 1995. Viruses have now been found on the IBM-PC, Apple II, Macintosh, Atari, and Amiga systems. There is some difference of opinion on the matter of Trojan Horses versus Viruses. A Trojan horse is a program that says or appears to be performing one function, while actually performing another.
Some experts say that viruses are not Trojan horses but can be part of a Trojan horse, while others say all viruses are Trojan horses, but not all Trojan horses are viruses. This explanation seems to make more sense, seeing as how no virus is labeled as one on an infected program. If a virus wasn t hidden, they would almost certainly cease to spread. Although there are thousands of Computer viruses, there are only about 500 of them in the wild. Anti-virus software itself contributes to many of the false alarms about computer viruses. A file can change its size and behavior for many different reasons not necessarily associated with a computer virus, but anti-virus software can interpret these changes as the presence of a virus.
There are still many misconceptions surrounding the way of which viruses can be contracted. Some believe reading an e-mail can cause ones system to contract a virus, this is incorrect. Simply reading the text of an e-mail is completely harmless. It is the attachments to an e-mail that can contain a virus, but a simple scan of the attachment before it is opened can reveal whether it is infected or not. Also, you cannot get a virus from looking at a webpage. A virus can only be contracted from an infected program copied from the site.
Downloading an infected file itself, is not even dangerous, the program must be run in order for the virus to infect a system. Although viruses are a threat to computer users all over the globe, the damage is less than most think. The paranoia caused by the viruses or even the virus hoaxes causes more damage than the viruses themselves. Those who create the anti-virus software do not tell the public this because widespread panic causes an increase in sales. Workers in businesses don t want to fix the problem because they know that their equipment can be replaced and updated if it s infected. The computer vendors don t dispel the myths, because they make more sales from people who believe their computers are lost.
The vendors then take the infected no good computers, clean the viruses and resell them for additional profit. Nobody really wants to fix a problem that helps the economy, even if it is detrimental to the public.
Free research essays on topics related to: computer viruses, trojan horses, hard drive, anti virus software, macro viruses
Research essay sample on Anti Virus Software Trojan Horses