Inference in Multilevel Secure Databases

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Inference in Multilevel Secure Databases

• Ryan Wakeham

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What is a Multilevel Secure DB?

• Historical Context
• DoD and Intel classification levels
• Inefficient
• Redundant databases
• Redundant workstations
• High cost
• Solution the MLS Database
• A single system combining data levels
• Technological controls to control access

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Woods Hole Architecture

• Trusted base operating system
• Separate instance of DBMS for each data level

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Trusted Subjects Architecture

• Trusted base operating system
• Single DBMS can access all data
• Trusted to only return authorized data

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What is Inference in MLS Databases?

• Occurs when a user is able to infer something
  about sensitive data through authorized queries
• Various different manifestations of inference
• Simple Example
• Secret XYZ Labs is working on the X-100 missile
  project
• Confidential Dr. Smith is attending a meeting
  about the X-100 development
• Unclassified Dr. Smith works for XYZ Labs

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Current Approaches to the Inference Problem

• Increase level of data classification
• Proper architecture
• Polyinstantiation
• Query-time inference control
• Primary area of future work
• More complex inference engines
• Possibly coupled with AI techniques

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References

• Farkas, Csilla, and Sushil Jajodia. "The
  Inference Problem A Survey." ACM SIGKDD
  Explorations Newsletter 4 (2002) 6-11.
• Hinke, Thomas H. "Inference Aggregation Detection
  in Database Management Systems." Proceedings of
  the 1988 IEEE Symposium on Security and Privacy
  (1988) 96-106.
• Lunt, Teresa F. "Aggregation and Inference Facts
  and Fallacies." Proceedings of the 1989 IEEE
  Symposium on Security and Privacy (1989)
  102-109.
• Null, Linda M., and Johnny Wong. "A Unified
  Approach for Multilevel Database Security Based
  on Inference Engines." Proceedings of the 20th
  SIGCSE Technical Symposium on Computer Science
  Education (1989) 108-111.
• Rjaibi, Walid. "An Introduction to Multilevel
  Secure Relational Database Management Systems."
  Proceedings of the 2004 Conference of the Centre
  for Advanced Studies on Collaborative Research
  (2004).
• Staddon, Jessica. "Dynamic Inference Control."
  Proceedings of the 8th ACM SIGMOD Workshop on
  Research Issues in Data Mining and Knowledge
  Discovery (2003) 94-100.