Optimal Strategies for Detecting Data Exfiltration by Internal and External Attackers

  • Karel Durkota
  • Viliam Lisý
  • Christopher Kiekintveld
  • Karel Horák
  • Branislav Bošanský
  • Tomáš Pevný
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 10575)

Abstract

We study the problem of detecting data exfiltration in computer networks. We focus on the performance of optimal defense strategies with respect to an attacker’s knowledge about typical network behavior and his ability to influence the standard traffic. Internal attackers know the typical upload behavior of the compromised host and may be able to discontinue standard uploads in favor of the exfiltration. External attackers do not immediately know the behavior of the compromised host, but they can learn it from observations.

We model the problem as a sequential game of imperfect information, where the network administrator selects the thresholds for the detector, while the attacker chooses how much data to exfiltrate in each time step. We present novel algorithms for approximating the optimal defense strategies in the form of Stackelberg equilibria. We analyze the scalability of the algorithms and efficiency of the produced strategies in a case study based on real-world uploads of almost six thousand users to Google Drive. We show that with the computed defense strategies, the attacker exfiltrates 2–3 times less data than with simple heuristics; randomized defense strategies are up to 30% more effective than deterministic ones, and substantially more effective defense strategies are possible if the defense is customized for groups of hosts with similar behavior.

Keywords

Data exfiltration detection Game theory Network security 

Notes

Acknowledgments

This research was supported by the Czech Science Foundation (grant no. 15-23235S).

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Copyright information

© Springer International Publishing AG 2017

Authors and Affiliations

  • Karel Durkota
    • 1
  • Viliam Lisý
    • 1
  • Christopher Kiekintveld
    • 2
  • Karel Horák
    • 1
  • Branislav Bošanský
    • 1
  • Tomáš Pevný
    • 1
    • 3
  1. 1.Deptartment of Computer Science, FEECzech Technical University in PraguePragueCzech Republic
  2. 2.Computer Science DepartmentUniversity of Texas at El PasoEl PasoUSA
  3. 3.Cisco Systems, Inc.PragueCzech Republic

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