1 Discovering Computers 2008
Chapter 11 Chapter 11 Chapter 11 Chapter 11 Computer Security, Computer Security, Computer Security, Computer Security, Ethics and Privacy Ethics and Privacy Ethics and Privacy Ethics and Privacy
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What are viruses, worms, and Trojan horses?
p. 558 Next
Virus Virusis a potentially damaging computer program
Worm Wormcopies itself repeatedly,
using up resources and possibly shutting down
computer or network
Trojan horse Trojan horsehides
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
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How can a virus spread through an e-mail message?
p. 559 Fig. 11-2 Next
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.
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Video: Attack of the Mobile Viruses
Next
CLICK TO START
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How can you protect your system from a macro virus?
p. 560 Fig. 11-3 Next
Set macro security level in applications that allow you to write macros
Set security level so that warning displays that document contains macro
Macrosare instructions saved in an application, such as word processing or spreadsheet program
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What is an antivirus program?
p. 560 - 561 Fig. 11-4 Next
Identifies and removes computer viruses
Most also protect against worms and Trojan horses
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What is a virus signature?
p. 561 Fig. 11-5 Next
Specific pattern of virus code Also called virus definition Antivirus programs
look for virus signatures
Keeps file in separate area of hard disk
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How does an antivirus program inoculatea program file?
p. 561 Next
Records Records information information about program such about program such as file size and as file size and creation creation date
date Attempts Attempts to remove to remove any detected any detected
virus virus Uses
Uses information information to detect if to detect if virus tampers virus tampers with file with file
Quarantines Quarantines infected infected files that it files that it cannot cannot remove remove
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What are some tips for preventing virus, worm, and Trojan horse infections?
p. 562 Next
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
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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What are a denial of service attack,back door and spoofing?
p. 562 and 563 Next
A denial of service attackis an assault which disrupts computer access to an Internet service
such as the Web or e-mail
A back dooris a program or set of instructions in a program that allow users to bypass security controls when accessing a computer
resource Spoofingis a technique intruders use to make
their network or Internet transmission appear legitimate to a victim computer or
network
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What is a firewall?
p. 563 Fig. 11-7 Next
Security system consisting of hardware and/or software that prevents unauthorized intrusion
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What is a personal firewall?
p. 564 Fig. 11-8 Next
Program that protects personal computer and its data from unauthorized intrusions
Monitors transmissions to and from computer
Informs you of attempted intrusion
Click to view Web Link, click Chapter 11, Click Web Link from left navigation, then click Personal Firewall Software below Chapter 11
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How can companies protect against hackers?
p. 564 - 565 Next
Intrusion detection software Intrusion detection software analyzes network traffic, assesses analyzes network traffic, assesses system vulnerabilities, and identifies system vulnerabilities, and identifies intrusions and suspicious behavior intrusions and suspicious behavior
Access control defines who Access control defines who can access computer and can access computer and what actions they can take what actions they can take
Audit trail
Audit trail records access records access attempts attempts
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What are other ways to protect your personal computer?
p. 565 Fig. 11-9 Next
Disable file and printer sharing on Internet connection
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What is a user name?
p. 566 Fig. 11-10 Next
Unique combination of characters that identifies user
Passwordis private combination of characters associated with the user name that allows access to computer resources
