Virus

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Virus
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What is a virus?

• A virus is a programme that is loaded onto your
  computer without your knowledge.
• Most viruses infect other programmes by
  modifying them to contain copies of themselves.

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Problems caused by viruses

• Some viruses are harmless to your system and
  produce annoying messages or sounds at random
  time.
• Others are quite dangerous by modifying the
  content or structure of the file system on your
  hard drive.

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Three main types of virus

• Boot sector viruses
• Programme viruses
• Macro viruses

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Boot sector viruses

• Attach themselves to floppy disks and them copy
  themselves to the boot sector of your hard drive
  whenever you turn on or reboot your computer.
• source only floppy disk

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Programme viruses

• Held within executable files that are associated
  with programs. They infect your computer when the
  file is executed.
• Common file types EXE, COM, (DLL, SYS, BIN)
• Source they are actually executed on your
  computer

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Macro viruses

• These viruses are developed to run in the macros
  that some programmes use.
• Common programmes used Microsofts Word, Excel

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Misconceptions

• Safe
• reading email message
• reading web pages
• downloading a file
• Dangerous
• open the attached file in a email
• executed a infected programme

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How to protect your computer

• Antivirus software
• call signatures or virus definitions
• update regularly the data of viruses
• scans the files, sectors and memory, then fixes
  viruses