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Meant for Year 6

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  1. 1. By Mr UVComputer Viruses and Worms
  2. 2. Definition of Virus
  3. 3. Computer Virus Timeline
  4. 4. Worms
  5. 5. History of Worms The first worm to attract wide attention, the Morris worm, was written by Robert Tappan Morris, who at the time was a graduate student at Cornell University. It was released on November 2, 1988 Morris himself was convicted under the US Computer Crime and Abuse Act and received three years probation, community service and a fine in excess of $10,000.
  6. 6. Worms… Worms – is a small piece of software that uses computer networks and security holes to replicate itself. A copy of the worm scans the network for another machine that has a specific security hole. It copies itself to the new machine using the security hole, and then starts replicating from there, as well. They are often designed to exploit the file transmission capabilities found on many computers.
  7. 7. Zombies
  8. 8. Typical things that some currentPersonal Computer (PC) viruses do
  9. 9. Typical things that some currentPersonal Computer (PC) viruses do
  10. 10. Distributed Denial of Service
  11. 11. How it works?
  12. 12. MyDoom
  13. 13.  27 January: SCO Group offers a US $250,000 reward for information leading to the arrest of the worms creator. 1 February: An estimated one million computers around the world infected with MyDoom begin the viruss massive distributed denial of service attack—the largest such attack to date. 2 February: The SCO Group moves its site to
  14. 14.  Traditional Viruses pieces of code attached to a legitimate program run when the legitimate program gets executed loads itself into memory and looks around to see if it can find any other programs on the disk
  15. 15.  Traditional Virus infect the boot sector on floppy disks and hard disks By putting its code in the boot sector, a virus can guarantee it gets executed load itself into memory immediately, and it is able to run whenever the computer is on
  16. 16. Decline of traditional viruses Reasons: – Huge size of today’s programs storing on a compact disk – Operating systems now protect the boot sector
  17. 17. E-mail Viruses Moves around in e-mail messages Replicates itself by automatically mailing itself to dozens of people in the victim’s e-mail address book Example: Melissa virus, ILOVEYOU virus
  18. 18.  March 1999 the Melissa virus was the fastest-spreading virus ever seen Someone created the virus as a Word document uploaded to an Internet newsgroup People who downloaded the document and opened it would trigger the virus The virus would then send the document in an e- mail message to the first 50 people in the persons address book
  19. 19. Melissa virus Took advantage of the programming language built into Microsoft Word called VBA (Visual Basic for Applications)
  20. 20. Prevention Updates Anti-Viruses More secure operating systems e.g. UNIX
  21. 21. Reference