Wong Pau Tung-special-topi-02-Virus
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Wong Pau Tung-special-topi-02-Virus - Presentation Transcript
Internet and Network Attacks
What are viruses , worms , and Trojan horses ?
p. 558 Virus is a potentially damaging computer program
Worm copies itself repeatedly, using up resources and possibly shutting down computer or network
Trojan horse hides within or looks like legitimate program until triggered Payload (destructive event) that is delivered when you open file, run infected program, or boot computer with infected disk in disk drive Can spread and damage files Does not replicate itself on other computers Next
Internet and Network Attacks
How can a virus spread through an e-mail message?
p. 559 Fig. 11-2 Step 1. Unscrupulous programmers create a virus program. They hide the virus in a Word document and attach the Word document to an e-mail message. Step 2. They use the Internet to send the e-mail message to thousands of users around the world. Step 3b. Other users do not recognize the name of the sender of the e-mail message. These users do not open the e-mail message. Instead they delete the e-mail message. These users’ computers are not infected with the virus. Step 3a. Some users open the attachment and their computers become infected with the virus. Next
Internet and Network Attacks Video: Attack of the Mobile Viruses Next CLICK TO START
Internet and Network Attacks
How can you protect your system from a macro virus?
p. 560 Fig. 11-3
Set macro security level in applications that allow you to write macros
Set security level so that warning displays that document contains macro
Macros are instructions saved in an application, such as word processing or spreadsheet program
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Internet and Network Attacks
What is an antivirus program ?
p. 560 - 561 Fig. 11-4
Identifies and removes computer viruses
Most also protect against worms and Trojan horses
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Internet and Network Attacks
What is a virus signature ?
p. 561 Fig. 11-5
Specific pattern of virus code
Also called virus definition
Antivirus programs look for virus signatures
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Internet and Network Attacks
How does an antivirus program inoculate a program file?
p. 561 Keeps file in separate area of hard disk Next Records information about program such as file size and creation date Attempts to remove any detected virus Uses information to detect if virus tampers with file Quarantines infected files that it cannot remove
Internet and Network Attacks
What are some tips for preventing virus, worm, and Trojan horse infections?
p. 562 Install a personal firewall program If the antivirus program flags an e-mail attachment as infected, delete the attachment immediately Never start a computer with removable media inserted Never open an e-mail attachment unless you are expecting it and it is from a trusted source Install an antivirus program on all of your computers Check all downloaded programs for viruses, worms, or Trojan horses Next Click to view Web Link, click Chapter 11, Click Web Link from left navigation, then click Virus Hoaxes below Chapter 11
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