Computer virus (Microsoft Word)

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Computer virus (Microsoft Word)

  1. 1. qwertyuiopasdfghjklzxcvbnmqwertyi uiopasdfghjklzxcvbnmqwertyuiopasd fghjklzxcvbnmqwertyuiopasdfghjklzx cvbnmqwertyuiopasdfghjklzxcvbnmq Computer Virus wertyuiopasdfghjklzxcvbnmqwertyui Name: Siti Ainiz Binti Bahari Class : 4 Iswara opasdfghjklzxcvbnmqwertyuiopasdfg 2013 hjklzxcvbnmqwertyuiopasdfghjklzxc vbnmqwertyuiopasdfghjklzxcvbnmq wertyuiopasdfghjklzxcvbnmqwertyui opasdfghjklzxcvbnmqwertyuiopasdfg hjklzxcvbnmqwertyuiopasdfghjklzxc vbnmqwertyuiopasdfghjklzxcvbnmq wertyuiopasdfghjklzxcvbnmqwertyui opasdfghjklzxcvbnmqwertyuiopasdfg hjklzxcvbnmrtyuiopasdfghjklzxcvbn mqwertyuiopasdfghjklzxcvbnmqwert yuiopasdfghjklzxcvbnmqwertyuiopas
  2. 2. What is virus? Computer viruses are small software programs that are designed to spread from one computer to another and to interfere with computer operation. A virus might corrupt or delete data on your computer, use your e-mail program to spread itself to other computers, or even erase everything on your hard disk. Viruses are most easily spread by attachments in e-mail messages or instant messaging messages. That is why it is essential that you never open e-mail attachments unless you know who it's from and you are expecting it. Viruses can be disguised as attachments of funny images, greeting cards, or audio and video files. Viruses also spread through downloads on the Internet. They can be hidden in illicit software or other files or programs you might download. To help avoid viruses, it's essential that you keep your computer current with the latest updates and antivirus tools , stay informed about recent threats , and that you follow a few basic rules when you surf the Internet, download files, and open attachments. Once a virus is on your computer, its type or the method it used to get there is not as important as removing it and preventing further infection .
  3. 3. A computer virus is a computer program that can copy itself and infect a computer without permission or knowledge of the user. The virus may also be purposly planted in order to cause confusion. The original 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 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, however, can spread itself to other computers without needing to be transferred as part of a host. A Trojan horse is a file that appears harmless until executed. In contrast to viruses, Trojan horses do not insert their code into other computer files. Many personal computers are now connected to the Internet and to local-area networks, facilitating their spread. 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 selfreplicating malware .
  4. 4. How do I remove a computer virus? If your computer is infected with a virus, you'll want to remove it as quickly as possible. A fast way to check for viruses is to use an online scanner, such as the Microsoft Safety Scanner. The scanner is a free online service that helps you identify and remove viruses, clean up your hard disk, and generally improve your computer's performance. If you're not sure whether your computer has a virus, see How can I tell if my computer has a virus? to check for some telltale signs. To try a different online scanner, follow the links to other companies that provide them on the Windows Security software providers webpage. To run the Microsoft Safety Scanner 1. Go to the Microsoft Safety Scanner webpage to download the scanner. 2. Click Download Now, and then follow the instructions on the screen. If you can't connect to the Internet If you can't get to the Microsoft Safety Scanner online, try restarting your computer in safe mode with networking enabled. To restart in Safe Mode with networking enabled 1. Restart your computer. 2. When you see the computer manufacturer's logo, press and hold the F8 key. 3. On the Advanced Boot Options screen, use the arrow keys to highlight Safe Mode with Networking, and then press Enter.
  5. 5. 4. Log on to your computer with a user account that has administrator rights. 5. Follow the steps above to run the Microsoft Safety Scanner. General Information About Computer Virus Different Malware Types Malware is a general name for all programs that are harmful; viruses, trojan, worms and all other similar programs. Viruses A computer virus is a program, a block of executable code, which attach itself to, overwrite or otherwise replace another program in order to reproduce itself without a knowledge of a PC user. There are a couple of different types of computer viruses: boot sector viruses, parasitic viruses, multi-partite viruses, companion viruses, link viruses and macro viruses. These classifications take into account the different ways in which the virus can infect different parts of a system. The manner in which each of these types operates has one thing in common: any virus has to be executed in order to operate. Most viruses are pretty harmless. The user might not even notice the virus for years. Sometimes viruses might cause random damage to data files and over a long period they might destroy files and disks. Even benign viruses cause damage by occupying disk space and main memory, by using up CPU processing time. There is also the time and expense wasted in detecting and removing viruses.
  6. 6. Trojan A Trojan Horse is a program that does something else that the user thought it would do. It is mostly done to someone on purpose. The Trojan Horses are usually masked so that they look interesting, for example a saxophone.wav file that interests a person collecting sound samples of instruments. A Trojan Horse differs from a destructive virus in that it doesn't reproduce. There has been a password trojan out in AOL land (the American On Line). Password30 and Pasword50 which some people thought were wav. files, but they were disguised and people did not know that they had the trojan in their systems until they tried to change their passwords. According to an administrator of AOL, the Trojan steals passwords and sends an E-mail to the hackers fake name and then the hacker has your account in his hands. Worm A worm is a program which spreads usually over network connections. Unlike a virus which attach itself to a host program, worms always need a host program to spread. In practice, worms are not normally associated with one person computer systems. They are mostly found in multi-user systems such as Unix environments. A classic example of a worm is Robert Morrisis Internet-worm 1988.
  7. 7. Other types of Virus Bacteria Bacteria, also known as rabbits, are programs that do not directly damage the the system. Instead they replicate themselves until they monopolize CPU, memory or disk space. This constitutes a denial of service attack. Bombs A bomb is actually a type of Trojan horse that can be used to release a virus or bacteria. Bombs work by causing an unauthorized action at a specified date, time or when a particular condition occurs. There are two types of bombs; logic and time. Logic bombs are set to go off when a particular event occurs. Time bombs go off at a specified time, date or after a set amount of time elapses. Salami Salamis cut away tiny pieces of data. They can be particularly dangerous as the damage they do is small and can be attributed to some truncation of the system. It is possible for a salami to do a great deal of damage before it is found.
  8. 8. HOW VIRUSES ACTIVE? We are always afraid that viruses do something harmful to files when they get active, but not all the viruses activate. Some viruses just spread out, but when viruses activate they do very different things. Might play a part of melody or play music in the background, show a picture or animated picture, show text, format hard disk or do changes to files. As an example, in one unnamed company: over a long period of time, the files in a server were corrupted just a bit. So backup copies were taken from the corrupted files. And after they noticed that something was wrong, it was too late to get back the data from the backups. That kind of event is the worst that can happen for the uses.
  9. 9. Conclusion There are lots of viruses in the world and new viruses are coming up every day. There are new anti-virus programs and techniques developed too. It is good to be aware of viruses and other malware and it is cheaper to protect you environment from them rather then being sorry. There might be a virus in your computer if it starts acting differently. There is no reason to panic if the computer virus is found. It is good to be a little suspicious of malware when you surf in the Internet and download files. Some files that look interesting might hide a malware. A computer virus is a program that reproduces itself and its mission is to spread out. Most viruses are harmless and some viruses might cause random damage to data files. A trojan horse is not a virus because it doesn't reproduce. The trojan horses are usually masked so that they look interesting. There are trojan horses that steal passwords and formats hard disks.
  10. 10. Reference http://en.wikipedia.org/wiki/Computer_virus http://windows.microsoft.com/enmy/windows7/how-do-i-remove-a-computer-virus

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