Assessing the Feasibility of Machine Learning to Detect Network - - PowerPoint PPT Presentation

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Assessing the Feasibility of Machine Learning to Detect Network - - PowerPoint PPT Presentation

Assessing the Feasibility of Machine Learning to Detect Network Covert Channels Name: Diogo Barradas PhD Stage: Planner Advisors: Prof. Lus Rodrigues & Prof. Nuno Santos Research Area: Privacy-Enhancing Technologies Diogo Barradas - EuroSys


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Diogo Barradas - EuroSys Doctoral Workshop 2018

Assessing the Feasibility of Machine Learning to Detect Network Covert Channels

Name: Diogo Barradas PhD Stage: Planner Advisors: Prof. Luís Rodrigues & Prof. Nuno Santos Research Area: Privacy-Enhancing Technologies

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Diogo Barradas - EuroSys Doctoral Workshop 2018

What’s All This About?

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  • What’s the Problem?

○ Current unobservability assessments of covert channels are flawed

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Diogo Barradas - EuroSys Doctoral Workshop 2018

What’s All This About?

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  • What’s the Problem?

○ Current unobservability assessments of covert channels are flawed

  • Why Should We Care?

○ Inaccurate unobservability assessments can place human lives in jeopardy

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Diogo Barradas - EuroSys Doctoral Workshop 2018

What’s All This About?

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  • What’s the Problem?

○ Current unobservability assessments of covert channels are flawed

  • Why Should We Care?

○ Inaccurate unobservability assessments can place human lives in jeopardy

  • What Are You Going To Do About It?

○ Develop a robust framework for the unobservability assessment of covert channels

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Diogo Barradas - EuroSys Doctoral Workshop 2018

What’s All This About?

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  • What’s the Problem?

○ Current unobservability assessments of covert channels are flawed

  • Why Should We Care?

○ Inaccurate unobservability assessments can place human lives in jeopardy

  • What Are You Going To Do About It?

○ Develop a robust framework for the unobservability assessment of covert channels

  • Then What?

○ Foster the design of new tools to circumvent repressive network control

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Diogo Barradas - EuroSys Doctoral Workshop 2018

Multiple Tools Generate Covert Channels in the Internet

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  • Recent approaches tunnel data through encrypted protocols

○ e.g. Skype

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Diogo Barradas - EuroSys Doctoral Workshop 2018

Covert Channels through Multimedia Protocol Tunneling

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Facet Unidirectional (A/V) Video Transmission DeltaShaper Bidirectional (V) Arbitrary Data Transmission

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Diogo Barradas - EuroSys Doctoral Workshop 2018

Adversaries can Learn from Encrypted Traffic

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  • Traffic analysis can detect unusual patterns in (encrypted) network flows
  • Covert data must be carefully modulated to evade detection

○ Security => Unobservability

Encrypted Traffic Analysis

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Diogo Barradas - EuroSys Doctoral Workshop 2018

Existing Unobservability Claims are Questionable

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  • Ad hoc covert channel evaluation

○ Similarity-based classifiers only ○ Unobservability measured against independently built classifiers

  • Lack of theoretical reasoning in covert channel design

○ Covert data embedding is guided through black-box experimentation

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Diogo Barradas - EuroSys Doctoral Workshop 2018

Research Questions

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  • Are state-of-the-art covert channels observable?
  • Can we better assess the unobservability of current tools?
  • Can we accurately characterize covert data carrier protocols?
  • Is it possible to provide theoretical bounds to unobservability?
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Diogo Barradas - EuroSys Doctoral Workshop 2018

Research Questions

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  • Are state-of-the-art covert channels observable?
  • Can we better assess the unobservability of current tools?
  • Can we accurately characterize covert data carrier protocols?
  • Is it possible to provide theoretical bounds to unobservability?
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Diogo Barradas - EuroSys Doctoral Workshop 2018

Similarity-Based Detection

  • Unobservability claims are dependent on the classifier
  • Similarity-based classifiers cannot accurately detect covert traffic

○ ROC AUC:

System / Classifier Chi-Square Earth Mover’s Distance Facet 0.83 0.58 DeltaShaper 0.74 0.57

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Diogo Barradas - EuroSys Doctoral Workshop 2018

Similarity-Based Detection

  • Unobservability claims are dependent on the classifier
  • Similarity-based classifiers cannot accurately detect covert traffic

○ ROC AUC:

System / Classifier Chi-Square Earth Mover’s Distance Facet 0.83 0.58 DeltaShaper 0.74 0.57

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Diogo Barradas - EuroSys Doctoral Workshop 2018

Decision Tree-Based Detection

  • Largely undermine previous unobservability claims

○ Facet: ROC AUC = 0.99 (vs 0.83) ○ DeltaShaper: ROC AUC = 0.95 (vs 0.74)

  • Provide us insight on useful features for identifying covert channels
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Diogo Barradas - EuroSys Doctoral Workshop 2018

Takeaways

  • Ensuring unobservability is desirable for covert channels
  • Past unobservability assessments are flawed
  • Goal: build a rigorous framework for the assessment of unobservability

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https://web.ist.utl.pt/diogo.barradas

Thank You!