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Virus Presentation Transcript

  • 1. Computer Virus 06/10/09
  • 2. What is a Computer Virus
    • A kind of software programs
      • produced by unknown people and harmful to the computers
    • Some varieties of these software are the
      • Viruses , Worms and Trojan horses
  • 3. What is a Computer Virus
    • The term “Virus" is often used in common
      • to describe all kinds of malware (malicious software)
  • 4. Damages done by Viruses
    • Sometimes display unwanted messages
    • Some tend to destroy programs or data
    • Clog computer memory and hence sometimes result in system crashes
    • Format hard disks, Damage programs, Delete files
    06/10/09 Viruses
  • 5. Damages done by Viruses
    • Simply replicate themselves
    • Presents text, video, or audio messages making the user know their presence
    • Bug-ridden, and these bugs may lead to system crashes and data loss
  • 6. Virus spreading methods
    • A viruses can copy itself and infect a computer
      • without permission or knowledge of the user
    • attaches itself to other software programs or data files
  • 7. Virus spreading methods
    • Spreads from computer to computer when the host is taken to the uninfected computer
      • over a network such as over the Internet or carrying it on a removable medium - a floppy disk, CD, or USB drive
  • 8. Virus spreading methods
    • Many viruses are existed in the Internet today and new ones are discovered every day.
      • spread via downloaded software and data files, and email attachments, etc
  • 9. Virus spreading methods
    • Some old viruses are installed themselves into the disk boot sector
      • runs when the user boot the computer from the disk
  • 10. Virus spreading methods
    • Some viruses spread through instant messaging
      • A virus, in an infected machine, may send a web-address-link as a message to other contacting machines
      • Thinking the link is from a friend (a trusted source), the recipient may sometimes follow the link to the websit.
  • 11. How Viruses are borne
    • Unlike biological viruses, computer viruses do not simply evolve by themselves
      • deliberately created by programmers, or by people who use virus creation software
  • 12. How Viruses are borne
    • Viruses are written as
      • research projects, pranks, vandalism,
      • to attack the products of specific companies,
      • to distribute political messages,
      • and financial gain from identity theft,
      • spyware, and cryptoviral extortion .
  • 13. How Viruses are borne
    • Some virus writers
      • consider their creations to be works of art
      • See virus writing as a creative hobby
    06/10/09 Releasing computer viruses is a crime in most jurisdictions
  • 14. Viruses can avoid detection
    • To avoid detection by users, viruses employ different deception methods
      • They do not make themselves to
        • change the date of last modified
        • increase file sizes
        • damage the files
  • 15. Viruses can avoid detection
      • They kill the tasks associated with antivirus software before it can detect them
  • 16. How Antivirus software works?
    • Detect using a list of virus signature definitions
      • comparing the files stored on fixed or removable drives (hard drives, floppy drives), against a database of known virus "signatures".
  • 17. How Antivirus software works?
    • Use a heuristic algorithm to find viruses based on common behaviors
      • Examin the content heuristics of the computer's memory (its RAM, and boot sectors)
  • 18. How Antivirus software works?
    • Some anti-virus programs gives you a real time protection
      • Examin files as they are being opened, downloaded, copied, accessed, and transmitted etc
  • 19. How Antivirus software works?
    • They need regular updates
      • in order to gain knowledge about the latest threats
  • 20. Damage prevention & data recovering
    • Take regular backups (including OS) on different media, unconnected to the system (most of the time)
    06/10/09 How to prevent damages caused by viruses?
  • 21. Damage prevention & data recovering
    • Use backups on optical media like CD and DVD (read-only), as they can no longer be affected by viruses.
    • Use an OS on a bootable, to start the computer if the installed OS become unusable.
    06/10/09 How to prevent damages caused by viruses?
  • 22. Keep your computer Virus free
    • Install reliable anti-virus software
      • the most important step you can take towards keeping your computer clean of viruses
    • Update your anti-virus software regularly
      • variations of viruses and new ones can be slipped if your software is not current
  • 23. Keep your computer Virus free
    • Get immediate protection
      • Configure your anti-virus software to boot automatically on start-up and run at all times
  • 24. Keep your computer Virus free
    • Don't automatically open attachments
      • ensure that you examine and scan email and other attachments before they run as they might contain viruses
    • Scan all incoming email attachments
      • Do not open any email attached files if the subject line is questionable, unexpected or the source (address) is unknown, suspicious or untrustworthy
  • 25. Keep your computer Virus free
    • Delete chain emails and junk email
      • Do not forward or reply to any of them, they clogs up the network
      • Some viruses can replicate themselves and spread through email as a chain
  • 26. Keep your computer Virus free
    • Be careful when downloading files from the Internet
      • Ensure that the source is a legitimate and reputable one
      • save all downloads to one folder and test them with your own anti-virus software before use
  • 27. Keep your computer Virus free
    • Always scan new files for viruses before you use them
  • 28. Keep your computer Virus free
    • Backup your files on a regular basis
  • 29. Keep your computer Virus free
    • If your computer is on a network, make sure you have security steps in place to prevent unauthorized users putting files on your computer
  • 30. Keep your computer Virus free
    • Take care using USB flash cards, CDs, zip and floppy disks
      • The more computers flash cards, CDs, zip cards and floppies have been used on, the better the chance of a virus infecting them – clean them before use
  • 31. END 06/10/09