C MU U sable P rivacy and S ecurity Laboratory User Interfaces and Algorithms for Fighting Phishing...

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CMU Usable Privacy and Security Laboratory http://cups.cs.cmu.edu/ User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate, Carnegie Mellon University Presented at IIS seminar, 1/30/2008

Transcript of C MU U sable P rivacy and S ecurity Laboratory User Interfaces and Algorithms for Fighting Phishing...

Page 1: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

CMU Usable Privacy and Security Laboratoryhttp://cups.cs.cmu.edu/

User Interfaces and Algorithms for Fighting Phishing

Steve ShengDoctoral Candidate, Carnegie Mellon UniversityPresented at IIS seminar, 1/30/2008

Xinguang Sheng
Please add explanations to this so that we can professors can understand through reading the explanations
Page 2: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Everyday Privacy and Security Everyday Privacy and Security ProblemProblem

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Page 3: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

This entire processknown as phishing

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Page 4: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Still a growing problemStill a growing problem

Estimated 1 in 122 emails are phishing

Average 31,000 unique phishing sites reported each month in 2007

Estimated 3.5 million people have fallen for phishing in 2006

Estimated $ 350m – $ 2b direct loss a year

More profitable to phish than rob the bank!

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Page 5: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Project: Supporting Trust Project: Supporting Trust DecisionsDecisions Goal: help people make better online trust

decisions• Currently focusing on anti-phishing

Large multi-disciplinary team project at CMU• Computer science, human-computer interaction,

public policy, social and decision sciences, CERT

Page 6: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Our Multi-Pronged ApproachOur Multi-Pronged Approach

Human side• Interviews to understand decision-making

• PhishGuru embedded training

• Anti-Phishing Phil game

• Understanding effectiveness of browser warnings

Computer side• PILFER email anti-phishing filter

• CANTINA web anti-phishing algorithm

Automate where possible, support where necessary

Page 7: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Our Multi-Pronged ApproachOur Multi-Pronged Approach

Human side• Interviews to understand decision-making

• PhishGuru embedded training

• Anti-Phishing Phil game

• Understanding effectiveness of browser warnings

Computer side• PILFER email anti-phishing filter

• CANTINA web anti-phishing algorithm

What do users know about phishing?

Page 8: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Interview StudyInterview Study

Interviewed 40 Internet users (35 non-experts) “Mental models” interviews included email

role play and open ended questions Brief overview of results (see paper for details)

J. Downs, M. Holbrook, and L. Cranor. Decision Strategies and Susceptibility to Phishing. In Proceedings of the 2006 Symposium On Usable Privacy and Security, 12-14 July 2006, Pittsburgh, PA.

Page 9: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Little knowledge of phishingLittle knowledge of phishing

Only about half knew the meaning of term “phishing”

55% say that they had never noticed an unexpected or strange-looking URL

55% reported being cautious when asked for sensitive financial information• But very few reported being suspicious of email

asking for passwords

Knowledge of financial phish reduced likelihood of falling for these scams• But did not transfer to other scams, such as an

amazon.com password phish

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Page 10: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Naive Evaluation StrategiesNaive Evaluation Strategies

The most frequent strategies don’t help much in identifying phish• This email appears to be for me

• It’s normal to hear from companies you do business with

• Reputable companies will send emails

“I will probably give them the information that they asked for. And I would assume that I had already given them that information at some point so I will feel comfortable giving it to them again.”

Page 11: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Summary of FindingsSummary of Findings

People generally not good at identifying scams they haven’t specifically seen before

People don’t use good strategies to protect themselves

Large-scale survey across multiple cities in the US confirm finding

Downs, J. S., Holbrook, M. B., and Cranor, L. F. Behavioral Response to Phishing. In eCrime ’07: Proceedings of the 2007 e-Crime Researchers summit

Page 12: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

OutlineOutline

Human side• Interviews to understand decision-making

• PhishGuru embedded training

• Anti-Phishing Phil game

• Understanding effectiveness of browser warnings

Computer side• PILFER email anti-phishing filter

• CANTINA web anti-phishing algorithm

Can we train people not to fall for phish?

Page 13: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Web Site Training StudyWeb Site Training Study

Laboratory study of 28 non-expert computer users

Asked participants to evaluate 20 web sites• Control group evaluated 10 web sites, took 15 min break to

read email or play solitaire, evaluated 10 more web sites

• Experimental group same as above, but spent 15 min break reading web-based training materials

Experimental group performed significantly better identifying phish after training• Less reliance on “professional-looking” designs

• Looking at and understanding URLs

• Web site asks for too much information

People can learn from web-based training materials,

if only we could get them to read them!

Page 14: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

How Do We Get People How Do We Get People Trained?Trained? Most people don’t proactively look for training

materials on the web

Companies send “security notice” emails to employees and/or customers

We hypothesized these tend to be ignored• Too much to read

• People don’t consider them relevant

• People think they already know how to protect themselves

Led us to idea of embedded training

Page 15: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Embedded TrainingEmbedded Training

Can we “train” people during their normal use of email to avoid phishing attacks? • Periodically, people get sent a training email

• Training email looks like a phishing attack

• If person falls for it, intervention warns and highlights what cues to look for in succinct and engaging format

P. Kumaraguru, Y. Rhee, A. Acquisti, L. Cranor, J. Hong, and E. Nunge. Protecting People from Phishing: The Design and Evaluation of an Embedded Training Email System. CHI 2007.

Page 16: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Subject: Revision to Your Amazon.com Information

Please login and enter your information

http://www.amazon.com/exec/obidos/sign-in.html

Embedded training exampleEmbedded training example

Page 17: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Intervention #1 – DiagramIntervention #1 – Diagram

Page 18: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Intervention #1 – DiagramIntervention #1 – Diagram

Explains why they are seeing this message

Page 19: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Intervention #1 – DiagramIntervention #1 – Diagram

Explains what aphishing scam is

Page 20: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Intervention #1 – DiagramIntervention #1 – DiagramExplains how to identifya phishing scam

Page 21: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Intervention #1 – DiagramIntervention #1 – DiagramExplains simple thingsyou can do to protect self

Page 22: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Intervention #2 – Comic Intervention #2 – Comic StripStrip

Page 23: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Summary of Evaluation ResultsSummary of Evaluation Results

Study setup: Role play as Bobby Smith at Cognix Inc going through companies emails• 10 participants in each condition, screened for novice

Evaluation I: Lab study comparing our prototypes to standard security notices• Existing practice of security notices is ineffective

• Embedded training is effective

• Comic strip intervention worked best

Evaluation II: • Have to fall for phishing email to be effective?

• How well do people retain knowledge?

Page 24: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Results of Evaluation #2Results of Evaluation #2 Have to fall for phishing email to be effective?

How well do people retain knowledge after a week?

Page 25: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Results of Evaluation #2Results of Evaluation #2 Have to fall for phishing email to be effective?

How well do people retain knowledge after a week?

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Page 26: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Results of Evaluation #2Results of Evaluation #2 Have to fall for phishing email to be effective?

How well do people retain knowledge after a week?

0.07

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0.64

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Page 27: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Anti-Phishing PhilAnti-Phishing Phil

A game to teach people not to fall for phish• Embedded training focuses on email

• Our game focuses on web browser

Goals• How to parse URLs

• Where to look for URLs

• Use search engines for help

S. Sheng, B. Magnien, P. Kumaraguru, A. Acquisti, L. Cranor, J. Hong, and E. Nunge. Anti-Phishing Phil: The Design and Evaluation of a Game That Teaches People Not to Fall for Phish. In Proceedings of the 2007 Symposium On Usable Privacy and Security, Pittsburgh, PA, July 18-20, 2007.

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Page 28: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Anti-Phishing PhilAnti-Phishing Phil

Page 29: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Page 30: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Page 31: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Page 32: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Page 33: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Page 34: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Summary of Evaluation of Anti-Summary of Evaluation of Anti-Phishing PhilPhishing Phil Test participants’ ability to identify phishing

web sites before and after training up to 15 min• 10 web sites before training, 10 after, randomized order

Evaluation I: Lab study• How do Phil perform with

existing training materials?

Evaluation II: Online study• How well do people retain what they

learned?

Page 35: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

ResultsResults

Phil had the best performance overall, with lowest false positives

Novice users improve by 47%, intermediate users by 25%

People remembered what they learned one week after the training

Over 52,000 people played the game in the last three months

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Steve Sheng
maybe also add some press for it.
Page 36: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Game resultsGame results

29.7%

59.9%

92.5%

77.5%

84.6%

93.5%

76.8%

85.0%

93.9%

0%

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60%

80%

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Novice (N = 46) Intermediate (N =256)

Expert (N = 372)

tota

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Pre testPost testOne Week Later

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Page 37: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/ 37

Page 38: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Page 39: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Teaching users about phishing attacks

can be a reality!

Page 40: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

OutlineOutline

Human side• Interviews to understand decision-making

• PhishGuru embedded training

• Anti-Phishing Phil game

• Understanding effectiveness of browser warnings

Computer side• PILFER email anti-phishing filter

• CANTINA web anti-phishing algorithm

Do people see, understand, and believe web browser warnings?

Page 41: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

ScreenshotsScreenshots

Internet Explorer – Passive Warning

Page 42: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

ScreenshotsScreenshots

Internet Explorer – Active Block

Page 43: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

ScreenshotsScreenshots

Mozilla FireFox – Active Block

Page 44: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

How Effective are these How Effective are these Warnings?Warnings? Tested four conditions

• FireFox Active Block

• IE Active Block

• IE Passive Warning

• Control (no warnings or blocks)

“Shopping Study”• Setup some fake phishing pages and added to blacklists

• Users were phished after purchases

• Real email accounts and personal information

• Spoofing eBay and Amazon (2 phish/user)

• We observed them interact with the warnings

Page 45: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

How Effective are these How Effective are these Warnings?Warnings?

Page 46: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

How Effective are these How Effective are these Warnings?Warnings?

Page 47: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Discussion of Phish WarningsDiscussion of Phish Warnings

Nearly everyone will fall for highly contextual phish

Passive IE warning failed for many reasons• Didn’t interrupt the main task

• Slow to appear (up to 5 seconds)

• Not clear what the right action was

• Looked too much like other ignorable warnings (habituation)

• Bug in implementation, any keystroke dismisses

Page 48: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

ScreenshotsScreenshots

Internet Explorer – Passive Warning

Page 49: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Discussion of Phish WarningsDiscussion of Phish Warnings

Active IE warnings• Most saw but did not believe it

“Since it gave me the option of still proceeding to the website, I figured it couldn’t be that bad”

• Some element of habituation (looks like other warnings)

• Saw two pathological cases

Egelman, S, Cranor, L, Hong, J. You’ve been Warned. In CHI 2008.

Page 50: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

ScreenshotsScreenshots

Internet Explorer – Active Block

Page 51: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

OutlineOutline

Human side• Interviews to understand decision-making

• PhishGuru embedded training

• Anti-Phishing Phil game

• Understanding effectiveness of browser warnings

Computer side• PILFER email anti-phishing filter

• CANTINA web anti-phishing algorithm

Can we automatically detect phish emails?

Page 52: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

PILFER Email Anti-Phishing FilterPILFER Email Anti-Phishing Filter

Philosophy: automate where possible, support where necessary

Goal: Create email filter that detects phishing emails• Spam filters well-explored, but how good for phishing?

• Can we create a custom filter for phishing?

I. Fette, N. Sadeh, A. Tomasic. Learning to Detect Phishing Emails. In W W W 2007.

Page 53: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

PILFER Email Anti-Phishing FilterPILFER Email Anti-Phishing Filter

Heuristics combined in SVM• IP addresses in link (http://128.23.34.45/blah)

• Age of linked-to domains (younger domains likely phishing)

• Non-matching URLs (ex. most links point to PayPal)

• “Click here to restore your account”

• HTML email

• Number of links

• Number of domain names in links

• Number of dots in URLs (http://www.paypal.update.example.com/update.cgi)

• JavaScript

• SpamAssassin rating

Page 54: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

PILFER EvaluationPILFER Evaluation

Ham corpora from SpamAssassin (2002 and 2003)• 6950 good emails

Phishingcorpus• 860 phishing emails

Page 55: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

PILFER EvaluationPILFER Evaluation

Page 56: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

PILFER EvaluationPILFER Evaluation

PILFER now implemented as SpamAssassin filter

Page 57: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

OutlineOutline

Human side• Interviews to understand decision-making

• PhishGuru embedded training

• Anti-Phishing Phil game

• Understanding effectiveness of browser warnings

Computer side• PILFER email anti-phishing filter

• CANTINA web anti-phishing algorithm

How good is phish detection for web sites?Can we do better?

Page 58: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Lots of Phish Detection Lots of Phish Detection AlgorithmsAlgorithms Dozens of anti-phishing toolbars offered

• Built into security software suites

• Offered by ISPs

• Free downloads (132 on download.com)

• Built into latest version of popular web browsers

Page 59: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Lots of Phish Detection Lots of Phish Detection AlgorithmsAlgorithms Dozens of anti-phishing toolbars offered

• Built into security software suites

• Offered by ISPs

• Free downloads (132 on download.com)

• Built into latest version of popular web browsers

But how well do they detect phish?• Short answer: still room for improvement

Page 60: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Testing the ToolbarsTesting the Toolbars

November 2006: Automated evaluation of 10 toolbars• Used phishtank.com and APWG as source of phishing URLs

• Evaluated 100 phish and 510 legitimate sites

Y. Zhang, S. Egelman, L. Cranor, J. Hong. Phinding Phish: An Evaluation of Anti-Phishing Toolbars. NDSS 2006.

Page 61: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Testbed System ArchitectureTestbed System Architecture

Page 62: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

ResultsResults

0%

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0 1 2 12 24

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Phi

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SpoofGuardEarthLinkNetcraftGoogleIE7CloudmarkTrustWatcheBayNetscapeMcAfee

38% false positives

1% false positives

PhishTank

Page 63: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

ResultsResults

Only one toolbar >90% accuracy (but high false positives)

Several catch 70-85% of phish with few false positives

Page 64: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

ResultsResults

Only one toolbar >90% accuracy (but high false positives)

Several catch 70-85% of phish with few false positives

Can we do better?• Can we use search engines to help find phish?

Y. Zhang, J. Hong, L. Cranor. CANTINA: A Content-Based Approach to Detecting Phishing Web Sites. In W W W 2007.

Page 65: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Robust HyperlinksRobust Hyperlinks

Developed by Phelps and Wilensky to solve “404 not found” problem

Key idea was to add a lexical signature to URLs that could be fed to a search engine if URL failed• Ex. http://abc.com/page.html?sig=“word1+word2+...+word5”

How to generate signature?• Found that TF-IDF was fairly effective

Informal evaluation found five words was sufficient for most web pages

Page 66: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Adapting TF-IDF for Anti-Adapting TF-IDF for Anti-PhishingPhishing Can same basic approach be used for anti-phishing?

• Scammers often directly copy web pages

• With Google search engine, fake should have low page rank

Fake Real

Page 67: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

How CANTINA WorksHow CANTINA Works

Given a web page, calculate TF-IDF score for each word in that page

Take five words with highest TF-IDF weights

Feed these five words into a search engine (Google)

If domain name of current web page is in top N search results, we consider it legitimate • N=30 worked well

• No improvement by increasing N

Later, added some heuristics to reduce false positives

Page 68: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Fake

eBay, user, sign, help, forgot

Page 69: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Real

eBay, user, sign, help, forgot

Page 70: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Page 71: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Page 72: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Evaluating CANTINAEvaluating CANTINAPhishTank

Page 73: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Weaknesses in CANTINAWeaknesses in CANTINA

Bad guys may try to subvert search engines

Only works if legitimate page is indexed• Intranets

May be confused if same login page in multiple places

Page 74: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

SummarySummary

Whirlwind tour of our work on anti-phishing• Human side: how people make decisions, training, UIs• Computer side: better algorithms for detecting phish

More info about our work at cups.cs.cmu.edu

Page 75: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

AcknowledgmentsAcknowledgments

Alessandro Acquisti

Lorrie Cranor

Sven Dietrich

Julie Downs

Mandy Holbrook

Norman Sadeh

Anthony Tomasic

Umut Topkara

Supported by NSF, ARO, CyLab, Portugal Telecom

• Serge Egelman• Ian Fette• Ponnurangam

Kumaraguru• Bryant Magnien• Elizabeth Nunge• Yong Rhee• Steve Sheng• Yue Zhang

Page 76: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

CMU Usable Privacy and Security Laboratoryhttp://cups.cs.cmu.edu/

Steve ShengEngineering and Public

[email protected]

Page 77: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Page 78: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Is it phish?Is it phish?

Our label

Yes No

Yes True positive False negative

No False positive True negative

Page 79: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Page 80: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Page 81: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Page 82: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Minimal Knowledge of Lock IconMinimal Knowledge of Lock Icon

“I think that it means secured, it symbolizes some kind of security, somehow.”

85% of participants were aware of lock icon

Only 40% of those knew that it was supposed to be in the browser chrome

Only 35% had noticed https, and many of those did not know what it meant

Page 83: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Solution SpaceSolution Space

83

Xinguang Sheng
Need more stuff here, what do I need here?How many spent on phishing?
Page 84: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Phishing continues to evolvePhishing continues to evolve

Spear-phishing on the rise for US military and other organizations aiming sensitive information

Voice over IP phishing becoming more prevalent

Phishing techniques continue to evolve

84

Xinguang Sheng
tell us the state of the problem here.
Page 85: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Research ProblemResearch Problem

As phishing continues to evolve, what can and should stakeholders do to better fight it?

85

Page 86: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Summary of Summary of Thesis StatementThesis Statement Identify phishing stakeholders and their stakes

Find gaps in the countermeasures pursued by each stakeholder

Generate and evaluate policy options to better fight phishing now and in the future

Case studies on the effectiveness of anti-phishing toolbars and game-based anti-phishing education

86

Page 87: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

OverviewOverview

Case study: Antiphishing toolbars

Case study: Antiphishing toolbars

Case study: Anti-phishing Phil

Case study: Anti-phishing Phil

87

Page 88: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

OutlineOutline

Background• Relevant literature

• Prior Work

Public Policy Analysis

Case Study in Anti-phishing toolbars

Case Study in User Education

Schedule

88

Page 89: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

OutlineOutline

Background• Relevant literature

• Prior Work

Public Policy Analysis

Case Study in Anti-phishing toolbars

Case Study in User Education

Schedule

89

Page 90: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

StakeholdersStakeholdersConsumers --Organizations US Military, Universities, CorporationsFinancial Institutions Bank of America, Citibank, Wachovia, PaypalMerchants eBay, AmazonInternet Service Providers SBC, Comcast, AOLEmail Providers Gmail, YahooMail, Hotmail, Outlook, ThunderbirdBrowsers Internet Explorer, Firefox, Safari, Opera, Netscape.DNS authorities Verisign, various NICsSoftware Vendors Google, Microsoft, Symantec, RSA, MarkMonitorLaw Enforcements Federal Bureau of Investigation(FBI), CERT, Secret

Service, Identity Theft Divisions in Law enforcements

Government Regulators Federal Financial Institutions Examination Council (FFIEC), Federal Trade Commission (FTC)

Academic Institutions Carnegie Mellon University, Indiana UniversityIndustry Consortium Financial Services Technology Council(FSTC), Anti-

Phishing Working Group (APWG), Messaging Anti-Abuse Working Group(MAAWG)

Direct stakeholders Indirect stakeholders

PrimaryVictimsSecondary VictimsVendors

Enforcement

Oversight / Coordination / Research

Market based

90

Xinguang Sheng
need to make sure estimate the problem.
Page 91: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Phishing CountermeasuresPhishing Countermeasures

91

Education

Page 92: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Economics of information Economics of information Security - ExternalitiesSecurity - Externalities

Does successfully combating phishing depends on the efforts of the laziest and most cowardly family? or the most valiant knight? or sum of efforts?

If it is all of above, which part requires what kinds of efforts?

92

Page 93: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

HypothesisHypothesis

Consumers are the weakest link

The problem can be solved if a solution has ubitiquous coverage and near perfect performance, and browsers are the most likely candidate.• In which case, phishers will use other channels

Effective law enforcements require the sum of all efforts

93

Page 94: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Longitudinal TrendsLongitudinal Trends

94

Page 95: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Estimating problemsEstimating problems

95

Page 96: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Estimating CountermeasuresEstimating Countermeasures

PhishingEmails

MailGateways

MailClients

End UserAction

Webbrowsers

User enters info

userknowledge

client filters warninggateway filters

MailStorage

storage filters

web mailclients

bank fraud

fraud detection

authenticationsystem

lawenforcements

1) What advantages, constraints does each stakeholder have in their phishing countermeasures? 2) What kind of solutions best fit each type of stakeholder?

96

Page 97: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Understanding ConstraintsUnderstanding Constraints

97

Page 98: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Expert InterviewsExpert Interviews

Goal: To further understand current and future phishing threats, relevant countermeasures, and with an eye on tomorrow, countermeasures should be put in place.

12 experts from industry associations, academia, industry, law enforcements, and volunteer organizations

98

Xinguang Sheng
tell me who are the stakeholders to interview?
Page 99: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Expert InterviewsExpert Interviews

Sectors Examples Number to Interview

Industry Associations Anti-Phishing Working Group (APWG), Messaging Anti-abuse Working Group (MAAWG), Financial Services Technology Council (FSTC)

2-3 officers

Industry Microsoft, Google, RSA, Symantec, MarkMonitor, McAfee, MessageLabs , and CloudMark

3-6 experts

Law Enforcements Federal Bureau of Investigation (FBI), Secret Service, CERT

2-4 experts

Academia CMU and other institutions 3-5 faculty

Volunteer Organizations PhishTank, CastleCorps 2 experts

99

Page 100: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

High Level QuestionsHigh Level Questions

Phishing threats• What do you think the current state of phishing?

• How phishing are costing various stakeholders?

• What kinds of attacks would likely to happen in the near future and long term?

Countermeasures• What kinds of solutions are stakeholders adopting?

• What are some effective ways to combat phishing?

• In light of the evolving phishing threats, what are some of the most promising ways?

• Is there anything missing in the countermeasures?

100

Page 101: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

High Level QuestionsHigh Level Questions

Policy Related• Who is the best position to solve the problem? and what

kind of solutions you see are lacking?

• What additional investments are needed?

• How should we prioritize our spending on prevention, detection, shutdown, and education?

• Where are we wasting our money at?

101

Page 102: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

MethodologyMethodology

Semi-structured interviews

Refine the objective and questions; outline a design; draft the interview questions; pilot test with 3 CMU experts, iterate on it more based on the results

Conduct interviews from May 2008 to October 2008

Follow up surveys with some organizations

102

Page 103: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

OverviewOverview

103

Page 104: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Gap AnalysisGap Analysis

Map countermeasures with attack vectors

Contrast stakeholders actions with expert analysis and recommendations

104

Page 105: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Gap AnalysisGap Analysis

Attack Prevention Detection Warning Block / Shutdown

Website

email

Instant Messaging

Auto Dialer

News, Chat Room, Blog

Bulletin Board

Wireless LANs

P2P or Interactive

Games

Malware

105

Page 106: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Phishing Life CyclePhishing Life Cycle

Source: Financial Service Technology Consortium, 2005

106

Page 107: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Phishing Life CyclePhishing Life Cycle

107

Page 108: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Why People fallWhy People fall

People judge a website's legitimacy by its “look and feel” (Rachna et al. 2006, Wu et al. 06)

Many do not understand or trust web browser indicator (Downs et al. 2007)

Awareness do not link to different behaviors or strategies (Downs et al. 2007)

Perceived severity of the consequences does not predict their behaviors (Downs et al. 2007)

108

Xinguang Sheng
Please add citations for literature
Page 109: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Cost of PhishingCost of Phishing

Direct costs• Consumers lose money, banking fraud

• Estimated 350 – 2 billion

Indirect costs• Erosion of consumer trust

• Impact on brand name

• Increase in customer call centers

Opportunity costs

109

Page 110: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Recent DevelopmentsRecent Developments

VOIP phishing

Spear phishing

Rock phish and fast flux

110

Page 111: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/ 111

Page 112: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Phil Online User StudyPhil Online User Study

Conducted in 9/25 – 10/10

Validate Lab study results

Test for retention of knowledge

Condition• Control: N = 2702 (12 websites + game)

• Game: N = 2021 (674 complete one week later) (6 website + game + 6 website + 6 website one week later)

112

Page 113: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Game resultsGame results

29.7%

59.9%

92.5%

77.5%

84.6%

93.5%

76.8%

85.0%

93.9%

0%

20%

40%

60%

80%

100%

Novice (N = 46) Intermediate (N =256)

Expert (N = 372)

tota

l co

rrec

tnes

s

Pre testPost testOne Week Later

113

Page 114: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Misidentifying Legitimate SitesMisidentifying Legitimate Sites

42.0%

30.1%

5.5%

11.2%7.9%

2.8%

12.3%

8.4%

2.5%

0%

10%

20%

30%

40%

50%

Novice (N = 46) Intermediate (N =256)

Expert (N = 372)

Fal

se P

osi

tive

Pre test

Post test

One Week Later

114

Page 115: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Falling for PhishingFalling for Phishing

28.3%

10.0%

2.0%

11.2%

7.4%

3.7%

10.9%

7.1%

3.7%

0%

10%

20%

30%

40%

Novice (N = 46) Intermediate (N= 256)

Expert (N = 372)

Fal

se N

egat

ive

Rat

e

Pre test

Post test

One Week Later

115

Xinguang Sheng
show me the latest update figure.
Page 116: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Comparing Control with GameComparing Control with Game

Control group performance• Pre test score: 70.9%

• Post test score:67.1%

The effect is not due to simply showing the quiz. (p<0.0001, N = 4674) (2 sample t test on (Score_post – Score_pre))

116

Page 117: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Signal detection theory Signal detection theory to measure learningto measure learning Users are learning well in the game

• d’_pre = 1.49, d’_post = 2.46 (p<0.001).

The improvement is not due to becoming more suspicious, in fact the reverse it true. • C’_pre = -0.352, C’_post = 0.016. (p<0.001)

117

Page 118: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Intervention #2 – Comic Intervention #2 – Comic StripStrip

Page 119: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Intervention #2 – Comic Intervention #2 – Comic StripStrip

Page 120: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Little Knowledge of PhishingLittle Knowledge of Phishing

Only about half knew meaning of the term “phishing”

“Something to do with the band Phish, I take it.”

Page 121: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Little Attention Paid to URLsLittle Attention Paid to URLs

Only 55% of participants said they had ever noticed an unexpected or strange-looking URL

Most did not consider them to be suspicious

Page 122: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Some Knowledge of ScamsSome Knowledge of Scams

55% of participants reported being cautious when email asks for sensitive financial info• But very few reported being suspicious of email

asking for passwords

Knowledge of financial phish reduced likelihood of falling for these scams• But did not transfer to other scams, such as an

amazon.com password phish

Page 123: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Embedded Training Evaluation Embedded Training Evaluation #1#1 Lab study comparing our prototypes to

standard security notices• Group A – eBay, PayPal notices

• Group B – Diagram that explains phishing

• Group C – Comic strip that tells a story

10 participants in each condition (30 total)• Screened so we only have novices

Go through 19 emails, 4 phishing attacks scattered throughout, 2 training emails too• Role play as Bobby Smith at Cognix Inc

Page 124: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Embedded Training ResultsEmbedded Training Results

0102030405060708090

100

Emails which had links in them

Pe

rce

nta

ge

of

use

rs w

ho

clic

ke

d

on

a li

nk

Group A Group B Group C

Page 125: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Embedded Training ResultsEmbedded Training Results

Existing practice of security notices is ineffective

Diagram intervention somewhat better• Though people still fell for final phish

Comic strip intervention worked best• Statistically significant

• Combination of less text, graphics, story?

Page 126: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Evaluation #2Evaluation #2

New questions:• Have to fall for phishing email to be effective?

• How well do people retain knowledge?

Roughly same experiment as before• Role play as Bobby Smith at Cognix Inc, go thru 16 emails

• Embedded condition means have to fall for our email

• Non-embedded means we just send the comic strip

• Also had people come back after 1 week

Kumaraguru, P., Rhee, Y., Sheng, S., Hasan, S., Acquisti, A., Cranor, L. F., and Hong, J. Getting users to pay attention to anti-phishing education: evaluation of retention and transfer. In eCrime ’07: Proceedings of the anti-phishing working groups 2nd annual eCrime researchers summit

Page 127: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

Page 128: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

A Science of A Science of WarningsWarnings

See the warning?

Understand?

Believe it?

Motivated?

Planning on refining this model for computer warnings

Page 129: C MU U sable P rivacy and S ecurity Laboratory  User Interfaces and Algorithms for Fighting Phishing Steve Sheng Doctoral Candidate,

Steve Sheng• CMU Usable Privacy and Security Laboratory • http://cups.cs.cmu.edu/

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Time (hours)

Phis

hin

g s

ites c

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ectly identified

SpoofGuard

EarthLink

Netcraft

Firefox w/Google

IE7

Cloudmark

TrustWatch

eBay

Netscape

CallingID

Firefox

APWG