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CS 305Social, Ethical, and Legal

Implications of Computing

Chapter 6Computer Networks and Security

Herbert G. Mayer, PSU CSHerbert G. Mayer, PSU CSstatus 6/25/2011status 6/25/2011

Slides derived from prof. Wu-Chang Feng Slides derived from prof. Wu-Chang Feng

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Syllabus

Malware Virus Worms Examples Backdoor Troyan Horse Rootkit Botnet Hackers and Phreaks Enforcement OIn-Class Exercise

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MalwareDef: Malware is unwanted SW attack, giving instructions Def: Malware is unwanted SW attack, giving instructions

to your computer to do something an attacker wants it to your computer to do something an attacker wants it to, such as:to, such as: Delete files to render your computer inoperable Infect other systems --worms, viruses Monitor activity --webcams, keystroke loggers Gather information on you, your habits, web sites you visit Provide unauthorized access --Trojans, backdoors Steal files, store illicit files Send spam or attack other systems Stepping stone to launder activity --frame you for a crime Hide activity --rootkits

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Types of Malware

VirusesViruses

WormsWorms

TrojansTrojans

BackdoorsBackdoors

Rootkits (user & kernel level)Rootkits (user & kernel level)

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What is a Virus?

Self-replicating piece of code that attaches itself to other Self-replicating piece of code that attaches itself to other programs; usually requires human interaction to programs; usually requires human interaction to propagatepropagate

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Two Virus Components

PayloadPayload The malicious/anti-social thing that viruses & worms do that

make them highly irritating Examples: wiping your hard drive, deleting files, encrypting

files for blackmail purposes

Propagation mechanismPropagation mechanism How do viruses spread?

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Virus Propagation

LocallyLocally Simplest method Write it to the file system

Local files, executables, documentsWrite it into the boot sector/operating system

Removable storageRemovable storage Initial viruses propagated through tapes and floppies Rarely target CDs specifically but

Chernobyl (CIH) on Yamaha CDR update CDNIMDA on Visual Studio .net in Korea

Modern mediaCompact Flash, SD, USB Keys

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Virus Propagation

NetworkNetwork Most common currently

Email (Iloveyou)WebNewsgroups (Melissa)P2P Networks (Fastrack, Gnutella, IRC, Torrent)

» 2003 study showed 45% of executable files downloaded from KaZaA had viruses or Trojan horses

» Beware of Warez!NFS, Samba mountsSocial networks

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Examples

BenignBenign Brain virus (1986)

Determine level of software piracy in Pakistan

MaliciousMalicious Michelangelo (1991)

Erased boot sector on March 6

Love bug (2000)Deleted filesCollected passwords and e-mailed themAuthor was a 23 year old Filipino CS studentNo hacking laws in Philippines so no prosecution

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Worms

A worm is a self-replicating piece of code that spreads A worm is a self-replicating piece of code that spreads via networks; usually does not require human via networks; usually does not require human interaction to propagateinteraction to propagate

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Virus vs. WormSimilaritiesSimilarities

Goal is to infect other machines Can contain a payload

VirusVirus Infects other files (must have executable sections) Transmitted via removable storage or network Require user interaction for propagation -- e.g. Open a file, boot from

floppy, launch an executable, click on e-mail attachment etc.

WormWorm Travels through the network only key May infect other files (might be cleared through reboot) Does not require human interaction Target misconfiguration or flaws/vulnerability in systems --buffer

overflows!

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Why are Worms Powerful?

Fast scalingFast scaling Can take over a vast number of machines, each of which will act as a

launch point to infect other machines

Goal: Infect 10,000 machineGoal: Infect 10,000 machine Serial example

Suppose an average of 1 hour per machine Includes time to find a vulnerable machine, as well as infecting it 10000 hours = 416 days > 1 year!

Worm example Again, suppose an average of 1 hour per machine, Infected machines will subsequently take an hour to infect another

» 1st hour: 1 infection» 2nd hour: 3 infections» 3rd hour: 7 infections» 14th hour: 16,383 infections = 714 times faster than serial

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Anatomy of Worm

A worm is composed ofA worm is composed of Warhead Propagation Engine Target Selection Algorithm Scanning Engine Payload

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Warhead

Warhead – the mechanism by which a worm gains entry Warhead – the mechanism by which a worm gains entry into a systeminto a system This is the part that we protect our systems against. The

warhead contains the exploit code Buffer overflow, copying into open file shares, password

attacks

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Propagation Engine

Propagation Engine – How the worm transports a new Propagation Engine – How the worm transports a new copy of itself into another machinecopy of itself into another machine Often, warheads contain the entire worm, but not always Warhead code can download the rest of the worm code, e.g.

remote root shell exploit followed by an ftp

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Target Selection Algorithm

Target Selection Algorithm – How a worm selects its Target Selection Algorithm – How a worm selects its next targetnext target Want to choose nearby targets. Nearby targets are much

faster to infect than far away targets IP address proximity, network neighborhood, e-mail address

books

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Scanning Engine

Scanning Engine – Code that probes machines to Scanning Engine – Code that probes machines to determine if addresses generated by the targeting determine if addresses generated by the targeting algorithm are vulnerable.algorithm are vulnerable. Pretty simple usually – send probing packets (TCP SYN) to

targets, wait for response If successful in opening a socket, attempt to compromise

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Payload

Payload – The malicious code that the worm actually Payload – The malicious code that the worm actually deliversdelivers Early worms often had no payload, just the mere act of

spreading itself around will damage the Internet Install a backdoor, Trojan, or rootkit Alter or destroy files (immediately, timed, on-demand) Encrypt your data, delete the originals, hold it for ransom Form a botnet (e-mail spam, search engine spam, phishing) Launch DoS attacks

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Examples

The first few worms were “ethical” worms – worms that The first few worms were “ethical” worms – worms that tried to perform a useful servicetried to perform a useful service

CreeperCreeper First worm developed for the assistance of air traffic

controllers by Bob Thomas in 1971 Notified air traffic controllers when the controls of a plane

moved from one computer to another Traveled from one computer screen to the other on the

network showing the message, "I'm creeper! Catch me if you can!"

Did not reproduce itself

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Examples

Xerox PARC wormsXerox PARC worms John Shock and Jon Hepps of Xerox PARC, early eighties Worms as efficient carriers of software

"town crier" worm posted announcements on all computers of network

More complex – activated only at night to consume unused CPU cycles

Escaped laboratory into Xerox’s networkOne morning the employees returned to find that all the

computers had crashed. When they tried to restart the computers, they crashed again

One of the worms malfunctioned and had created havoc in the network

A "vaccine" had to be created so as to deactivate the worm

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Examples

The Internet worm (1988)The Internet worm (1988) Robert Morris (student at Cornell) discovers multiple security holes

in Unix (ftp, sendmail, and fingerd) Wanted to research whether one could create an automated means for

exploiting them Goal was to infect quickly, but do no other damage (i.e. files left alone) In the middle of the design, a patch was released for one vulnerability Morris quickly launched worm before it was completed

Released November 2, 1988 Brought down the Internet Morris suspended from Cornell and convicted of felony under U.S.

Computer Fraud and Abuse act. (Given probation) Went back to school at Princeton, now a professor at MIT

Ethics? Malicious or selfish?

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Code Red (2001)

Targeted indexing service used in Windows IIS web Targeted indexing service used in Windows IIS web serverserver Spreads as a bad HTTP request (buffer overflow)

Infected server creates 99 threads to attack random IP addresseswindowsupdate.microsoft.com was infected too

Infection rateOver 20,000 infections in less than 10 minutesOver 250,000 infections in less than 9 hoursOver 975,000 total infections

PayloadDDoS attack against whitehouse.gov’s IP

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Code Red (2001)

People don’t patchPeople don’t patch IIS vulnerability was fixed months before Code Red launched Infected machines observed years later

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Santy (2004)

Attacks PHP Bulletin Board (phpBB) website software.Attacks PHP Bulletin Board (phpBB) website software. Exploit

URL descrambling error in PHP on input allows arbitrary PHP script to execute.

Novel target selection algorithm How do you find vulnerable phpBB2 software to attack?

» The same way you do. It Googles for it.

» 40000 phpBB2 servers hit Google eventually started blocking/censoring searches to slow down worm Result: New variant of Santy used AOL and Yahoo search engines

“Ethical” worm developed 1 week later Anti-Santy worm used same method Google used Defaced webpage: “viewtopic.php secured by Anti-Santy-Worm V4. Your

site is a bit safer, but upgrade to >= 2.0.11.”

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Ethical WormsSuppose you create a worm that…Suppose you create a worm that…

Exploits the vulnerability Patches the system Removes itself Should you release it?

What if it spreads out of control? What if it spreads out of control?

What if it doesn’t work? What if it doesn’t work? Patching could bring about problems

E.g. Critical application depends on vulnerability to work correctly E.g. Application depends on a certain interpretation of the specification

Patches have to be tested thoroughly!

Are ethical worms an oxymoron?Are ethical worms an oxymoron? Perhaps not worth the trouble?

How would one analyze this using ethical frameworks?How would one analyze this using ethical frameworks?

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Ethical Disclosure

Publishing zero-day exploitsPublishing zero-day exploits Zero-Day worms especially dangerous as they target brand new

exploits No patch available! (Have to hope that your system/network is

adequately hardened) Is it ethical to disclose such vulnerabilities? How long should one wait to disclose them?

Publishing better ways to design wormsPublishing better ways to design worms Staniford, Paxson, Weaver, “How to 0wn the Internet in your own

spare time”, in Usenix Secuirty 02 Warhol Worms/Flash Worms Infect the entire Internet in 15 minutes/30 seconds. (!) Is it ethical to disclose such techniques?

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Backdoors

A backdoor is a program that allows attackers to bypass A backdoor is a program that allows attackers to bypass normal security controls on a system, gaining access normal security controls on a system, gaining access on the attacker’s own termson the attacker’s own terms

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Types of BackdoorsLocal escalation of privilegesLocal escalation of privileges

Allow attackers with account administrator privileges

Remote execution of individual commandsRemote execution of individual commands Remote attackers can send a message to a victim machine

that allows them to execute a single command on the victim machine

Remote command-line access (aka remote shell)Remote command-line access (aka remote shell) Remote attacker can type directly into a command prompt of

the victim machine across the network

Remote control of GUIRemote control of GUI Remote attacker controls the GUI of the victim machine

across the network

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Trojan Horse

A Trojan horse is a program which appears to have A Trojan horse is a program which appears to have some useful or benign capability, but conceals some some useful or benign capability, but conceals some hidden, malicious functionalityhidden, malicious functionality

Origin of term: The ancient Greeks laying siege to Origin of term: The ancient Greeks laying siege to Troy…Troy…

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Rootkits

Rootkits are Trojan backdoor tools that modify existing Rootkits are Trojan backdoor tools that modify existing operating system software so that attacker can keep operating system software so that attacker can keep access to and hide on a machineaccess to and hide on a machine

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Botnets

A bot is a software program that responds to commands A bot is a software program that responds to commands sent by a command-and-control program located on sent by a command-and-control program located on an external computeran external computer

Botnets are coordinated collections of bots under a Botnets are coordinated collections of bots under a single central controlsingle central control Launch denial-of-service attacks Send spam Host phishing sites

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Hackers and Phreaks

Hackers – two definitions: good and badHackers – two definitions: good and bad Someone highly skilled in programming and use of computer

systems (sign of respect in some circles) Someone that breaks into computer systems (sign of bad

behavior in public circles)

Phone phreak – someone that manipulates the Phone phreak – someone that manipulates the telephone system in order to communicate with telephone system in order to communicate with others without payingothers without paying Stealing access codes, using outlawed hardware

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Early Hacking Incidents

PDP-11PDP-11 Programmable minicomputer shared by many students at MIT Students forbidden to modify hardware Stewart Nelson (1960s)

Added a new hardware instruction in the middle of the night to “improve” performance

Also did it to demonstrate his skills

Ethical evaluationDoes it depend on the outcome?What good is an ethical framework if you can only tell afterwards

if an action is right or wrong?

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U.S. Law on HackingComputer Fraud and Abuse ActComputer Fraud and Abuse Act

Transmitting code that causes damage to a computer system Accessing without authorization any computer connected to

the Internet Transmitting classified government information Trafficking in computer passwords Computer fraud Computer extortion Maximum penalty – 20 years and $250k fine

Other acts that can be applied to Internet-based crimeOther acts that can be applied to Internet-based crime Wire Fraud Act National Stolen Property ace Identity Theft and Assumption Deterrence Act

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Recent Enforcement

Ancheta (2005)Ancheta (2005) Created botnet of hundreds of thousands of machines

Some within the DoD Used to spam

Arrested and convicted under Computer Fraud Abuse act and CAN-SPAM act in May 2005

57 months in prison, $15,000 in restitution to US government Forfeiture of illegal proceeds and computer equipment

Gonzalez (2009)Gonzalez (2009) With Russian co-conspirators, obtained 130 million credit/debit card

numbers Indicted

Success of enforcement few and far between due to stealth Success of enforcement few and far between due to stealth measures that are easy to implementmeasures that are easy to implement

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Blue Security

Fighting bots with botsFighting bots with bots Users sign up for Blue Security service Whenever they mark a message as spam, inform

BlueSecurity service Blue Security bot automatically sends opt-out message to

spammer Spammers target Blue Security and its users with enormous

volume of spam Service discontinued

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In-Class Exercise

Oberlin College in Ohio requires that every computer Oberlin College in Ohio requires that every computer brought to campus by a student be inspected for brought to campus by a student be inspected for viruses. System administrators remove all viruses viruses. System administrators remove all viruses from the students’ computers. Students whose from the students’ computers. Students whose computers subsequently pick up and spread a virus computers subsequently pick up and spread a virus may be fined $25, whether they knew about the virus may be fined $25, whether they knew about the virus or not. Is this a morally justifiable policy?or not. Is this a morally justifiable policy?

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In-Class Exercise

SATAN hacker toolkitSATAN hacker toolkit Security Administrator Tool for Analyzing Networks Probe computers for security weaknesses Could be used for good and evil Morality of publishing SATAN using ethical frameworks?

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In-Class Exercise

On-line votingOn-line voting Used in many countries to render elections cheap, easily accessible

Local elections in the UK (since 2001) U.S. primary elections in Alaska and Arizona (2000)

Controversial Election goals

Tamper-resistance» One vote per person» Prevent vote trading/selling» Audit trail to ensure proper tallying» Authenticating both the voter and the election service

Privacy Ease of use to avoid voter disenfranchisement (e.g. “Butterfly” ballot of

2000) Ethical evaluation?