Virus, Trojan Horse, and Worm

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Virus, Trojan Horse, and Worm

• Gang Pang
• MIS

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What is Computer Virus?

• Definition of Computer Virus
• A virus is a computer program that replicates
  itself.
• Unchecked replication is like computer cancer
  ultimately, the virus consumes the computers
  resources.
• Virus can cope itself and infect a computer
  without the permission or knowledge of the user.
• 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.

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Types of Virus and effect (Cont.)

• Different virus effect different areas of the
  computer and they infect the computer in
  varieties of different ways
• Worms
• A worm is a self-reproducing program which can
  travel over networks using networking mechanisms,
  without requiring any software or hardware
  support (such as a hard drive, a host program, a
  file, etc.) to spread a worm is therefore a
  network virus.
• worms spread mainly with email clients using
  attachments that contain instructions for
  gathering all email address found in the address
  book and sending copies of themselves to all of
  these receivers.
• These worms are usually scripts or executable
  files sent as an attachment, which trigger when
  the receiver clicks on the attachment.
• When people accidentally open the files that
  contain worm, any executable files can be
  interpret, may potentially infect your computer.
  Files with the following extensions, in
  particular, may potentially be infected
• exe, com, bat, pif, vbs, scr, doc, xls, msi, eml

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Types of Virus and effect (Cont.)

• Trojan horses
• A Trojan horse is a computer program which
  carries out malicious operations without the
  user's knowledge.
• It is a hidden program which secretly runs
  commands, and usually opens up access to the
  computer running it by opening a backdoor.
• Infection by a Trojan horse usually comes after
  opening a infected file that containing the
  Trojan horse and is indicated by the following
  symptoms
• Abnormal activity by the modem, network adapter
  or hard drive data is being loaded without any
  activity from the user
• Strange reactions from the mouse
• Programs opening unexpectedly
• Repeated crashes.

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Types of Virus and effect (Cont.)

• Macro Viruses
• A macro is an instruction that carries out
  program commands automatically. Macro virus is
  the most common type of viruses.
• Macro viruses are macros that self-replicate. If
  a user accesses a document containing a viral
  macro and unknowingly executes this macro virus,
  it can then copy itself into that application's
  startup files.
• Any document on that machine that uses the same
  application can then become infected.
• If the infected computer is on a network, the
  infection is likely to spread rapidly to other
  machines on the network.
• Macro viruses can be written with very little
  specialist knowledge, and these viruses can
  spread to any platform on which the application
  is running.

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How can people prevent virus?

• There are many different ways to prevent virus
  crush your computer
• Use firewall, know where you surf and what you
  download or upload, update more often and be
  alert with e-mails or messages, use Firefox it
  helps to prevent virus to get into your computer.
• Do not open email attachment unless you expect to
  receive it. There is always a possibility that
  the attachments might contain new virus that the
  anti-virus software is not able to detect it at
  all.
• Avoid share files to others. Apply strong
  password to protect you machine. Do not leave
  administrator password blank or assigning trivial
  password with your Windows machine.
• The most important part of protect you computer
  install some kind of Anti-virus program. Which it
  can help people detect, eliminate virus and fix
  any virus problem people have on their
  computers.

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References

• http//www.microsoft.com/protect/computer/basics/v
  irus.mspx
• http//en.kioskea.net/virus
• http//www.virusall.com/macro.shtml