Chapter 6: Computer and Network Security

Copyright © 2011 Pearson Education, Inc. Publishing as Pearson Addison-Wesley

Ethics for the Information AgeFourth Edition

by Michael J. Quinn

Chapter 6: Computer and Network Security

1-2

Copyright © 2011 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1-2

Chapter Overview

• Introduction• Viruses, worms, and Trojan horses• Phreaks and hackers• Denial-of-service attacks• Online voting

1-3


6.1 Introduction

• Computers getting faster and less expensive• Utility of computers increasing

– Email– Web surfing– Shopping– Managing personal information

• Increasing use of computers growing importance of computer security

1-4


6.2 Viruses, Worms, andTrojan Horses

1-4

1-5


Viruses

• Virus: piece of self-replicating code embedded within another program (host)

• Viruses associated with program files– Hard disks, floppy disks, CD-ROMS– Email attachments

• How viruses spread– Diskettes or CDs– Email– Files downloaded from Internet

1-6


How a Virus Replicates

1-6

1-7


Email Attachment with Possible Virus

1-7

1-8


How an Email Virus Spreads

1-8

1-9


History of Viruses

• Well-known viruses– Brain– Michelangelo– Melissa– Love Bug

• Viruses today– Good news: Commercial antivirus software– Bad news: Few people keep up-to-date

1-10


Worms

• Worm– Self-contained program– Spreads through a computer network– Exploits security holes in networked computers

• Famous worms– WANK– Code Red– Sapphire (Slammer)– Blaster– Sasser

1-11


How a Worm Spreads

1-11

1-12


Three Kinds of Buffer Overflow Attack

1-12

1-13


Conficker (Downadup) Worm

• Appeared on Windows computers in November 2008

• Uses a buffer overflow attack to spread to new computers

• Particularly difficult to eradicate• Rate of new infections roughly the same as

rate of eradications

1-13

1-14


The Internet Worm

• Robert Tappan Morris, Jr.– Graduate student at Cornell– Released worm onto Internet from MIT computer

• Effect of worm– Spread to 6,000 Unix computers– Infected computers kept crashing or became unresponsive– Took a day for fixes to be published

• Impact on Morris– Suspended from Cornell– 3 years’ probation + 400 hours community service– $150,000 in legal fees and fines

1-15


Ethical Evaluation

• Kantian evaluation– Morris used others by gaining access to their computers

without permission

• Social contract theory evaluation– Morris violated property rights of organizations

• Utilitarian evaluation– Benefits: Organizations learned of security flaws– Harms: Time spent by those fighting worm, unavailable

computers, disrupted network traffic, Morris’s punishments

• Morris was wrong to have released the Internet worm

1-16


Trojan Horses

• Trojan horse: program with benign capability that masks a sinister purpose

• Remote access Trojan: Trojan horse that gives attack access to victim’s computer– Back Orifice– SubSeven

• RAT servers often found within files downloaded from erotica/porn Usenet sites

1-17


Bot Networks

• Bot: A software program that responds to commands from a program on another computer

• Some bots support legitimate activities– Internet Relay Chat– Multiplayer Internet games

• Other bots support illegitimate activities– Distributing spam– Collecting person information for ID theft– Distributed denial-of-service attacks

1-18


Defensive Measures

• System administrators play key role• Authorization: determining that a user has

permission to perform a particular action• Authentication: determining that people are

who they claim to be• Firewall: a computer monitoring packets

entering and leaving a local area network

1-19


6.3 Phreaks and Hackers

1-19

1-20


Hackers (original meaning)

• Original meaning– Explorer– Risk-taker– Technical virtuoso

• Hacker ethic– Hands-on imperative– Free exchange of information– Mistrust of authority– Value skill above all else– Optimistic view of technology

1-21


Hackers (evolved meaning)

• Meaning of “hacker” changed– Movie WarGames– Teenagers accessing corporate or

government computers• Dumpster diving• Social engineering

– Malicious acts• Destroying databases• Stealing confidential personal information

1-22


Phone Phreaking

• Phone phreak: someone who manipulates phone system to make free calls

• Most popular methods– Steal long-distance telephone access codes– Guess long-distance telephone access codes– Use a “blue box” to get free access to long-

distance lines

• Access codes posted on “pirate boards”

1-23


The Cuckoo’s Egg

• Clifford Stoll: system administrator at Lawrence Berkeley Laboratory

• Tracked accounting error, discovered unauthorized user

• Hacker was accessing military computers• FBI, CIA, NSA, AFOSI, DIA joined search• Trail led to group of West German hackers

1-24


Legion of Doom

• Elite group of hackers/phreaks recruited by “Lex Luthor”

• LOD member Robert Riggs copied E911 Document from a Bell South Computer

• Craig Neidorf published edited E911 Document in his BBS magazine, Phrack

1-25


U.S. v. Riggs

• Riggs and Neidorf arrested– Charged with wire fraud– Interstate transportation of stolen property valued at

$79,449– Computer fraud

• Riggs pleaded guilty to wire fraud; went to federal prison

• Neidorf pleaded not guilty– Defense showed similar info being sold for < $25– Prosecution moved to dismiss charges

1-26


Steve Jackson Games

• Steve Jackson Games (SJG) published role-playing games and operated BBS

• Loyd Blankenship– Key SJG employee– LOD member– Published E911 document on his own BBS

• Secret Service raided SJG and seized computers, looking for copy of E911 Document

• Led to creation of Electronic Frontier Foundation• EFF backed successful SJG lawsuit of Secret

Service

1-27


Retrospective

• Parallels between hackers and those who download MP3 files– Establishment overvalues intellectual property– Use of technology as a “joy ride”– Breaking certain laws considered not that big a deal

• Parallels between response of Secret Service and response of RIAA– Cyberspace is real– Those who break the law can be identified– Illegal actions can have severe consequences

1-28


Penalties for Hacking

• Examples of illegal activities– Accessing without authorization any Internet

computer– Transmitting a virus or worm– Trafficking in computer passwords– Intercepting a telephone conversation, email, or any

other data transmission– Accessing stored email messages without

authorization– Adopting another identity to carry out an illegal

activity• Maximum penalty: 20 years in prison + $250,000

fine

1-29


6.4 Denial-of-Service Attacks

• Denial-of-service attack: an intentional action designed to prevent legitimate users from making use of a computer service

• Goal of attack: disrupt a server’s ability to respond to its clients

• About 4,000 Web sites attacked each week• Asymmetrical attack that may prove popular with

terrorists

1-30


Attacks that Consume Scarce Resources

• SYN flood attack• Smurf attack• Fill target computer’s hard disk

– Email bombing– Worm– Break-in followed by file copying

1-31


How a SYN Flood Attack Works

1-31

1-32


How a Smurf Attack Works

1-32

1-33


Defensive Measures

• Physical security of server• Benchmarking• Disk quota systems• Disabling unused network services• Turning off routers’ amplifier network

capability

1-34


Distributed Denial-of-Service Attacks

• Attacker gains access to thousands of computers

• Launches simultaneous attack on target servers

• Defensive measures– Secure computers to prevent hijackings– Check for forged IP addresses

1-35


The Rise and Fall of Blue Security Part I: The Rise

• Blue Security: An Israeli company selling a spam deterrence system

• Blue Frog bot would automatically respond to each spam message with an opt-out message

• Spammers started receiving hundreds of thousands of opt-out messages, disrupting their operations

• 6 of 10 of world’s top spammers agreed to stop sending spam to users of Blue Frog

1-35

1-36


The Rise and Fall of Blue Security Part II: The Fall

• One spammer (PharmaMaster) started sending Blue Frog users 10-20 times more spam

• PharmaMaster then launched DDoS attacks on Blue Security and its business customers

• Blue Security could not protect its customers from DDoS attacks and virus-laced emails

• Blue Security reluctantly terminated its anti-spam activities

1-36

1-37


Fourth of July Attacks

• 4th of July weekend in 2009: DDoS attack on governmental agencies and commercial Web sites in United States and South Korea

• Attack may have been launched by North Korea in retaliation for United Nations sanctions

1-37

1-38


Attacks on Twitter and Other Social Networking Sites

• Massive DDoS attack made Twitter service unavailable for several hours on August 6, 2009

• Three other sites attacked at same time: Facebook, LiveJournal, and Google

• All sites used by a political blogger from the Republic of Georgia

• Attacks occurred on first anniversary of war between Georgia and Russia over South Ossetia

1-38

1-39


SATAN

• Security Administrator Tool for Analyzing Networks (SATAN)

• Allows administrators to test their systems• Could be used to probe other computers• Critics worried SATAN would turn unskilled

teenagers into hackers• That never happened

1-40


6.5 Online Voting

1-40

1-41


Motivation for Online Voting

• 2000 U.S. Presidential election closely contested• Florida pivotal state• Most Florida counties used keypunch voting

machines• Two voting irregularities traced to these

machines– Hanging chad– “Butterfly ballot” in Palm Beach County

1-42


The Infamous “Butterfly Ballot”

1-42

AP/Wideworld Photos

1-43


Benefits of Online Voting

• More people would vote• Votes would be counted more quickly• No ambiguity with electronic votes• Cost less money• Eliminate ballot box tampering• Software can prevent accidental over-voting• Software can prevent under-voting

1-44


Risks of Online Voting

• Gives unfair advantage to those with home computers• More difficult to preserve voter privacy• More opportunities for vote selling• Obvious target for a DDoS attack• Security of election depends on security of home

computers• Susceptible to vote-changing virus or RAT• Susceptible to phony vote servers• No paper copies of ballots for auditing or recounts

1-45


Utilitarian Analysis

• Suppose online voting replaced traditional voting• Benefit: Time savings

– Assume 50% of adults actually vote– Suppose voter saves 1 hour by voting online– Average pay in U.S. is $18.00 / hour– Time savings worth $9 per adult American

• Harm of DDoS attack difficult to determine– What is probability of a DDoS attack?– What is the probability an attack would succeed?– What is the probability a successful attack would change

the outcome of the election?

1-46


Kantian Analysis

• The will of each voter should be reflected in that voter’s ballot

• The integrity of each ballot is paramount• Ability to do a recount necessary to guarantee

integrity of each ballot• There should be a paper record of every vote• Eliminating paper records to save time and/or

money is wrong

1-47


Conclusions

• Existing systems are highly localized• Widespread tainting more possible with online

system• No paper records with online system• Evidence of tampering with online elections• Relying on security of home computers means

system vulnerable to fraud• Strong case for not allowing online voting

Documents

Chapter 6: Computer and Network Security