Computer virus


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Computer virus

  2. 2. What is computer virus <ul><li>A computer virus is computer programming, or code, that hides in computer programs or on the boot sector of storage devices such as hard-disk drives and floppy-disk drives. </li></ul>
  3. 3. Purpose of virus <ul><li>The primary purpose of a computer virus is to reproduce itself as often as possible. </li></ul><ul><li>Another purpose is to disrupt the operation of the computer or the program. This self-replicating program spreads by inserting copies of itself into other executable code or documents. </li></ul>
  4. 4. How will it spread? <ul><li>A computer virus behaves in a way similar to a biological virus, which spreads by inserting itself into living cells </li></ul><ul><li>The insertion of the virus into a program is termed infection, and the infected file (or executable code that is not part of a file) is called a host. </li></ul>
  5. 5. Types of virus <ul><li>Depends on spread time </li></ul><ul><li>There are two types of bombs, time bombs and logic bombs. Time bombs occur during a particular date or time. Logic bombs occur when the user of a computer takes an action that triggers the bomb. </li></ul>
  6. 6. Types <ul><li>Depends on spreading method </li></ul><ul><li>Viruses are one of the several types of malware or malicious software. In common the term virus is often extended to refer to computer worms and other sorts of malware. </li></ul><ul><li>Trojan horse viruses </li></ul>
  7. 7. Virus infections <ul><li>Some viruses have a delayed payload, which is sometimes called a bomb. For example, a virus might display a message on a specific day or wait until it has infected a certain number of hosts. </li></ul><ul><li>While viruses can be intentionally destructive </li></ul>
  8. 8. <ul><li>The predominant negative effect of viruses is their uncontrolled self-reproduction, which wastes or overwhelms computer resources </li></ul><ul><li>Virus programs can delete files, format disks, attack other computers or just make your system run slowly. </li></ul><ul><li>They can also create a &quot;back door&quot; that allows a hacker to run programs on your computer or to access into your files. </li></ul>
  9. 9. <ul><li>A computer infected with a virus may suddenly act in unexpected ways. </li></ul><ul><li>For example, it may take longer to access files or to start up programs, or it may lock up often. You may also notice uncommon sounds being played from your speakers, a variety of images popping up on the screen, or problems starting your computer.. </li></ul>
  10. 10. Symptoms of worms and Trojan horse viruses in e-mail messages <ul><li>When a computer virus infects e-mail messages or infects other files on a computer, you may notice the following symptoms: </li></ul>
  11. 11. <ul><li>The infected file may make copies of itself. This behavior may use up all the free space on the hard disk. </li></ul><ul><li>A copy of the infected file may be sent to all the addresses in an e-mail address list. </li></ul><ul><li>The computer virus may reformat the hard disk. This behavior will delete files and programs. </li></ul>
  12. 12. <ul><li>The computer virus may install hidden programs, such as pirated software. This pirated software may then be distributed and sold from the computer. </li></ul><ul><li>The computer virus may reduce security. This could enable intruders to remotely access the computer or the network. </li></ul><ul><li>You receive an e-mail message that has a strange attachment. When you open the attachment, dialog boxes appear, or a sudden degradation in system performance occurs. </li></ul>
  13. 13. <ul><li>Someone tells you that they have recently received e-mail messages from you that contained attached files that you did not send. The files that are attached to the e-mail messages have extensions such as .exe, .bat, .scr, and .vbs extensions. </li></ul>
  14. 14. THANK YOU
  15. 15. ANY QUESTIONS?
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