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CS 305Social, Ethical, and LegalImplications of Computing

Chapter 6Computer Networks and Security

Herbert G. Mayer, PSU CSHerbert G. Mayer, PSU CSstatus 6/24/2012status 6/24/2012

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

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Syllabus

Malware Virus Worms Examples Backdoor Trojan Horse Rootkit Botnet Hackers and Phreaks Enforcement In-Class Exercise

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Malware Malware: unwanted SW attack, instructing Malware: unwanted SW attack, instructing

your computer to do something an attacker your computer to do something an attacker wants, but you don’t want, such as:wants, but you don’t want, 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 Self-replicating piece of code that attaches itself to other programs; usually requires itself to other programs; usually requires human interaction to propagatehuman interaction to propagate

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Two Virus Components

PayloadPayload The malicious/anti-social action that viruses & worms perform that make them highly irritating or worse

Examples: wiping your hard drive, deleting files, encrypting files for blackmail purposes

Propagation mechanismPropagation mechanism How do viruses spread?

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Virus PropagationLocallyLocally

Simplest method Write to file system

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

Removable storageRemovable storage Initial viruses propagated through tapes and floppies

Today through thumb drives and CDs 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, 1991

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

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Virus vs. WormSimilaritiesSimilarities

Goal is to infect other machines Both may 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 or simply open an email

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 control of a vast number of machines, each of which will act as a launch point to infect other machines

Goal: Infect 10,000s of machinesGoal: Infect 10,000s of machines 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 Warhead – the mechanism by which a worm gains entry into a systemgains entry into a system This is the part that we protect our systems against. The warhead contains the exploitation code

Buffer overflow, copying into open file shares Password attacks

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Propagation Engine

Propagation Engine – How the worm transports Propagation Engine – How the worm transports a new copy of itself into another machinea new copy 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 Target Selection Algorithm – How a worm selects its next targetselects its next 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 Scanning Engine – Code that probes machines to determine if addresses generated by the to determine if addresses generated by the targeting algorithm are vulnerable.targeting 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 Payload – The malicious code that the worm actually deliversactually delivers 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 – The first few worms were “ethical” worms – worms that tried to perform a useful serviceworms that tried 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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ExamplesXerox 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

Infamous, accidental Internet worm (1988)Infamous, accidental 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 Targeted indexing service used in Windows IIS web serverIIS web server Spreads as a bad HTTP request (buffer overflow)

Infected server creates 99 threads to attack random IP addresses

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

Origin of term: The ancient Greeks laying Origin of term: The ancient Greeks laying siege to Troy, gaining access via a “loaded” siege to Troy, gaining access via a “loaded” horsehorse

That famous horse is generally spelled the That famous horse is generally spelled the “Trojan Horse”“Trojan Horse”

Yet the term, alluding to infamously sneaky Yet the term, alluding to infamously sneaky access to your computer system, is seen as access to your computer system, is seen as being spelled “Troyan Horse”being spelled “Troyan Horse”

A Trojan Horse is a program which appears to A Trojan Horse is a program which appears to have some useful or benign capability, but have some useful or benign capability, but conceals some hidden, malicious conceals some hidden, malicious functionalityfunctionality

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Rootkits

Rootkits are Trojan backdoor tools that Rootkits are Trojan backdoor tools that modify existing operating system software modify existing operating system software so that attacker can keep access to and so that attacker can keep access to and hide on a machine without owner’s consenthide on a machine without owner’s consent

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Botnets

Short for: network of robots, or roShort for: network of robots, or robot netbot net

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

Botnets are coordinated collections of bots Botnets are coordinated collections of bots under a single central controlunder a single 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 telephone system in order to communicate with others without payingwith others 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 Other acts that can be applied to Internet-based crimecrime

Wire Fraud Act National Stolen Property ace Identity Theft and Assumption Deterrence Act

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Recent EnforcementAncheta (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 Success of enforcement few and far between due to stealth measures that are easy to implementstealth measures 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 Oberlin College in Ohio requires that every computer brought to campus by a student be computer brought to campus by a student be inspected for viruses. System inspected for viruses. System administrators remove all viruses from the administrators remove all viruses from the students’ computers. Students whose students’ computers. Students whose computers subsequently pick up and spread computers subsequently pick up and spread a virus may be fined $25, whether they a virus may be fined $25, whether they knew about the virus or not. Is this a knew about the virus or not. Is this a morally justifiable policy?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?