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Web Authentication using Third-parties in Untrusted Environments - - PowerPoint PPT Presentation

Web Authentication using Third-parties in Untrusted Environments Anna Vapen PhD Thesis Presentation 2016-09-30 Supervisors: Nahid Shahmehri, Niklas Carlsson ***** 3 Agenda 1. Background 2. Research problems 3. Analysis Web


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Web Authentication using Third-parties in Untrusted Environments

Anna Vapen PhD Thesis Presentation 2016-09-30 Supervisors: Nahid Shahmehri, Niklas Carlsson

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*****

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Agenda

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1. Background 2. Research problems 3. Analysis

– Web authentication and untrusted computers – The third-party authentication landscape – Third-parties and privacy risks

4. Contributions

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Background

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****

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Web Authentication

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  • Method to prove that you are a

specific person

  • Personal web experience

– User accounts require authentication Background

Example: Signing in to Google with username and password

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Password Challenges

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Background Most common web authentication method Simple setup Replay attacks Forgotten by the user Reused on several sites Written down Alternative methods Time consuming Additional equipment

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Mobile Users and Untrusted Environments

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  • Mobile users

– Different devices – Different places Background

  • Untrusted environments

– Infected computer – Untrusted WiFi network

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Third-party Web Authentication

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  • Use an IDP (identity provider) account to access many

RPs (relying parties)

  • Fewer logins – simplify authentication
  • Information sharing between websites

– Privacy leaks! Background

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Third-party Authentication Scenario

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Redirect Logged in

Relying party (RP)

Background

Identity provider (IDP)

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Research Problems

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Research Problems

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1. Web authentication

– For mobile users in untrusted environments?

2. Third-party authentication

– Usage over time? – How to measure?

3. Privacy risks

– Information flows between parties? Research problems

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Web Authentication and Untrusted Computers

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Mobile Phones as Authentication Devices

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Web authentication

Strong authentication Carried by the user Security problems Comparing solutions?

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Design and Evaluation Method

  • Design

– Select requirements – Get design suggestions

  • Evaluation

– Start with an existing design – Get a security rating of the design Web authentication

Login Security rating Login Requirements

  • Security
  • Availability

PrimeLife’11

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Optical Authentication Proof-of-Concept

Web authentication

(1) Challenge barcode shown on screen (2) Take a picture

  • f the challenge

(3) Response generated (4) Show response to webcam

Logged in!

IJMCMC’11

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The Third-party Authentication Landscape

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Data Collection

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  • Popularity-based logarithmic sampling

– 80,000 points uniformly on a logarithmic range – Pareto-like distribution – Capturing data from different popularity segments

3rd-party authentication

1 million most popular websites Sampled websites

PAM’14

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Large-scale Crawling

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  • Selenium-based crawling and relationship identification
  • Able to process Web 2.0 sites with interactive elements
  • Low number of false positives
  • Validation with semi-manual classification and text-

matching

3rd-party authentication

Sampled websites

1 mil

PAM’14

Crawl sites to depth 2

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Collected Data

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3rd-party authentication

25 million analyzed links 3 329 unique relationships 50 IDPs and 1 865 RPs WHOIS, server location, and audience location Total site size and number

  • f links and objects

1.6 terabyte analyzed data

PAM’14, IC’16

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IDPs vs Content Sharing Services

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3rd-party authentication

Content sharing: Importing images, scripts etc. from other sites (third-party content providers) IDPs are selected locally, in contrast to content services.

PAM’14

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Service-based Analysis of RPs

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3rd-party authentication

Likely to be IDPs Early adopters, using several IDPs Using social/portal IDPs

Social/portal News Tech Video Info

File sharing

Commerce

Ad services, CDNs PAM’14 Manual analysis: Top 200 websites in April 2012

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Third-parties and Privacy Risks

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App Rights and Information Flows

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Privacy risks

App rights example

IDP RP

Actions: Write Update/remove Read

SEC’15, UEOP’16

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Our Studies on Privacy Risks

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  • Categorization app-rights data

– Manual study on the top 200 most popular websites – Longitudinal approach: three years

  • Targeted login tests
  • Privacy risk categorization

– Data types in app rights – Combinations of types Privacy risks

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Protocol Selection

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  • OpenID

– Authentication protocol – Decreasing in popularity

  • OAuth

– RP may use actions on IDP – Rich user data is shared – Increasingly popular

OAuth OpenID Both April 2012 vs. Sept 2014

  • 11%

+24%

Privacy risks

SEC’15, UEOP’16

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IDP Selection

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  • Top 200 April 2012: 69 RPs and 180 relationships
  • Same sites, April 2015: +15 RPs and +33 relationships
  • 75% of these RPs are selecting all their IDPs from the top

5 most popular IDPs

Privacy risks

Top IDPs:

+

37%

+

19%

+

12% SEC’15, UEOP’16

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Risk Types

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Facebook, Twitter and Google:

  • Only a few relationships in the most

privacy preserving category

  • 2+ IDPs: More than half are using

actions

– Dangerous when having several IDPs – Potential multi-hop leakage

51%

actions

2+ IDPs Privacy risks

SEC’15

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Multi-account Information Risks

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  • Cross account leakage
  • Unwanted

combinations of conflicting information

  • RPs handle multi-IDP

usage badly

Private photos

Privacy risks

IDP 1 IDP 2 RP This is me! Connecting several IDPs to an RP SEC’15

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Structures in the RP-IDP Landscape

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IDP HY RP

Hybrid case

  • Hybrids are both RP and IDP

Hybrid: RP and IDP

High-degree IDP case

  • IDP having many RPs
  • Top IDPs

IDP RP1 RP2

High-degree RP case

  • RP having many IDPs
  • Specialized IDPs

IDP1 IDP2 RP

Privacy risks

UEOP’16

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RP-to-RP Leakage Example

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RP-to-RP leaks February 2014 April 2015 IDP All Severe All Severe Facebook 645 150 473 66 Twitter 110 110 110 110 Google 91 91 IDP RP1 RP2 RP-to-RP

  • Potential RP-to-RP leaks

– Data posted to IDP from RP1 – Data read from IDP to RP2

Dataset with 44 RPs using Facebook, 14 using Twitter and 12 using Google

Privacy risks

UEOP’16

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Contributions

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Contributions

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  • Design and evaluation method
  • Large-scale RP-IDP measurements

– Novel measurement method – Categorization of RP-IDP relationships

  • Privacy risks and information sharing

– Protocol analysis – Structural properties Contributions

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Web Authentication using Third-parties in Untrusted Environments Anna Vapen

Papers included in this thesis:

  • Security Levels for Web Authentication using Mobile Phones, PrimeLife'11
  • 2-clickAuth - Optical Challenge-Response Authentication using Mobile

Handsets, IJMCMC'11

  • Third-party Identity Management Usage on the Web, PAM'14
  • A Look at the Third-Party Identity Management Landscape, IC'16
  • Information Sharing and User Privacy in the Third-party Identity

Management Landscape, SEC'15

  • Longitudinal Analysis of the Third-party Authentication Landscape,

UEOP'16