Transcript Lecture 7

Technology In Action Chapter 7
Technology In Action
Chapter 7
Networking and Security: Connecting
Computers and Keeping Them Safe from
Hackers and Viruses
© 2006 Prentice-Hall, Inc.
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Technology In Action Chapter 7
Networking Fundamentals
• Computer network:
– Two or more computers connected together
• Network Designs:
– Locally controlled:
 Peer-to-peer (P2P)
– Centrally controlled:
 Client/server
• Describe network based on distance
– LAN
– WAN
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Technology In Action Chapter 7
Network Components
• Transmission media
Telephone wire:
– Data transfer rate
T
wi
st
ed
pa
ir
• Network adapters
– Network Interface Cards (NIC)
– External Network Adapter
• Navigation devices
– Hubs
– Routers
Coaxial cable
Fiber-optic cable
Radio waves:
Wireless
• Network software
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Technology In Action Chapter 7
Peer-to-Peer Networks
• Types of P2P networks
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Power line
Phone line
Ethernet
Wireless
• Things to consider:
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Existing wiring
Wireless or wired
Speed of the network
Cost of the network
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Technology In Action Chapter 7
Computer Threats
• Cyber-crime, Cyber-criminal
• Hackers:
– Who they are
– What they do
 Steal information from computers:
 Internet packet sniffing
 Commit identity theft
 Create widespread computer attacks:
 Denial of service attacks
– How they gain access
 Direct access:
– Hacking software
 Indirect access:
– Internet connection
– Logical ports
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Technology In Action Chapter 7
Movie
• The Net (1995)
http://movieweb.com/movie/thenet
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Technology In Action Chapter 7
Computer Safeguards
• Firewalls
• Viruses and antivirus software
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Technology In Action Chapter 7
Firewalls
• Software programs or hardware designed
to close logical ports to invaders
• Types of firewalls:
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Norton Personal Firewall
McAfee Firewall
Zone Alarm
BlackICE PC Protection
Network routers
• Static addressing
• Dynamic addressing
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Technology In Action Chapter 7
Software firewall download
• ZoneAlarm—
http://www.zonelabs.com/store/content/c
atalog/products/sku_list_za.jsp?lid=pdb_z
al
• Sygate— http://soho.sygate.com/
• Norton Personal Firewall—
http://www.symantec.com/sabu/nis/npf/
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Technology In Action Chapter 7
Computer Viruses
• A program that attaches itself to another
program and spreads itself to other
computers
• Viruses are hidden within the code of a
host program
Norton AntiVirus Response Center
Web Page
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Technology In Action Chapter 7
What Viruses Do
• Replicate themselves:
– Slow down networks
• Secondary objectives:
– Annoying messages
– Delete files on the hard drive
– Change computer settings
Love Letter – Fastest
spreading virus
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Melissa – Caused $80
million damage
Nimda – Affected
more than 1 million
computers
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Technology In Action Chapter 7
Types of Viruses
• Boot-sector viruses:
– Replicate themselves in the boot sector of the hard drive
• Logic bombs:
– Activate when certain conditions are met
– Michelangelo virus
• Worms:
– Travel between systems through networks
– Sasser worm
March 6
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Technology In Action Chapter 7
Types of Viruses
• Script viruses:
– Hidden on Web pages
– Mini programs
• Macro viruses:
– Attached to documents
– Series of commands
– Melissa virus
• Trojan horses:
– Backdoor programs
– Control remote computers
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Technology In Action Chapter 7
Virus Classifications
• Polymorphic viruses:
– Periodically rewrite themselves to avoid detection
• Multipartite viruses:
– Infect multiple file types
• Stealth viruses:
– Erase their code from the hard drive and reside in the
active memory
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Technology In Action Chapter 7
Antivirus Software
• Programs designed to detect viruses:
– Scan files looking for virus signatures (unique code)
– Provides options for deleting or fixing infected files
• Detect known viruses
• Antivirus programs need to be updated
frequently
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Technology In Action Chapter 7
Chapter 7 Summary Questions
• What is a firewall and how does it keep
my computer safe from hackers?
• From which types of viruses do I need to
protect my computer?
• What can I do to protect my computer
from viruses?
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