20120709 cyber patterns2012


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20120709 cyber patterns2012

  1. 1. Extending AOP Principles for theDescription of Network SecurityPatternsDavid Llewellyn-Jones, Qi Shi, Madjid MerabtiCyberpatterns 2012, Abingdon, Oxfordshire, UK, 10th July 2012PROTECTResearch Centre for Critical Infrastructure Computer Technology and ProtectionSchool of Computing and Mathematical SciencesLiverpool John Moores University, Byrom Street, Liverpool L3 3AF, UKEmail: D.Llewellyn-Jones@ljmu.ac.ukWeb: http://www.ljmu.ac.uk/cmp/
  2. 2. Overview• Aspect Oriented Programming• Security concerns• Specifying network security point-cuts – Requirements – Examples – Language• Application Example• Conclusion
  3. 3. • Ensuring Trustworthiness and Security in Service Composition• http://www.aniketos.eu/• The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant no 257930 (Aniketos)
  4. 4. • Monitoring; trust and security analysis; recomposition and adaptation
  5. 5. Aspect Oriented Programming• Programming or development paradigm• Object Oriented Programming – Encapsulates related data and functionality all in one place – Hierarchical classes • Inheritance • Generalisation • Class attribute – Hard to capture cross-cutting concerns
  6. 6. Cross-Cutting Concerns
  7. 7. Aspect Oriented Programming• Orthogonal to Object Oriented Programming• Cross-Cutting Concerns – Similar functionality – Multiple places throughout• Example – Data logging
  8. 8. Security Concerns• Security – Classic cross-cutting concern – Apply in many places throughout code – Requires consistent approach• Examples – Authorisation – Access control – Data tagging
  9. 9. AOP Glossary• Aspect – The feature to be added• Join-Point – Potential• Point-Cut – Actual• Advice – Code to be injected• Aspect weaving – The process of adding advice to code
  10. 10. Join-Points• Join-points – Method calls – Initialisation – Get/set• Application – Before – After – Around• Dictates power of AOP technique
  11. 11. Join-Point Example<pointcut_definition id="c1"> <time>after</time> <joinpoint_type> <constructorcall> <constructor_signature> <qualified_class_name> <namespace><type_name>*</type_name></namespace> <class><identifier_name>FormCipher</identifier_name></class> </qualified_class_name> </constructor_signature> </constructorcall> </joinpoint_type></pointcut_definition><advice_definition idAdvice="DandelionAspectAddClient" idTypeOfInjection="StaticInjection"> <assembly>Gryffindor.Aspect.Dandelion.dll</assembly> <type>Gryffindor.Aspect.Dandelion.DandelionAspect</type> <behaviour>AddEncrypter</behaviour> <priority>1</priority> <pointcut_definitionRef idRef="c1"/></advice_definition>
  12. 12. Reflection• Aspects can be inserted at compile time – Static aspect weaving• Introspection – Allow analysis of code at runtime• Intercession – Allow code to be altered at runtime – Insert new code, redefine language• Allows aspects inserted at runtime – Dynamic aspect weaving
  13. 13. Network Security• Ideal, in theory – Apply aspects to services at runtime – Improve security based on dynamic composition and policy• Problematic, in practice – Point-cuts apply to single codebase – Applied universally – Distributed systems need different but related techniques in different places
  14. 14. Encryption Aspects Communication Encrypt Decrypt Communication• Often need to apply to multiple systems – Different related aspects – Not naturally covered by existing join-point definition languages• Need language to define this
  15. 15. Join-Point Language Requirements1. Capture sequences of more than two systems2. Match multiple sets of networked systems3. Be determinate4. Based on code and relationship between systems5. Aspect code related to join-point and existing code
  16. 16. Secure Data ForwardingH HL LH L H
  17. 17. End-to-End SecurityA B B B B AA B B B B A
  18. 18. Separation of Duty BA B BA B
  19. 19. Patterns• We aim to define a language for defining patterns• Combine with existing in-code join-point definitions• Allow complex relationships between networked systems to be defined• Both global and distributed application
  20. 20. Multiple Join-Point Definition• Notation
  21. 21. Patterns• Single template• Pattern of templates
  22. 22. Secure Data ForwardingH L H
  23. 23. End-to-End SecurityA B B B B A
  24. 24. Separation of Duty BA B
  25. 25. AOP Applied to Security • Client-Server chat application – Cleartext communication • Encryption/Decryption service • Aspects re-route data flowCommunication – Different aspects for client and server Miguel García, David Llewellyn-Jones, Francisco Ortin, Madjid Merabti, "Applying dynamic separation of aspects to distributed systems security: a case study", IET Software, Volume 6, Issue 3, pp. 165-282, June 2012.
  26. 26. AOP Applied to Security Communication Communication Communication
  27. 27. Discussion• Why choose this method? – Flexibility – Aim for all computable sets of networks – Distributed or centralised• Practical application – Definition and aspects still to be combined• Challenges – Difficult to define – Aspects are specialised, not generalised
  28. 28. Future Work• Practical – Restatement in XML format – Integrate with join-point definition language – Reason and apply to real code• Theoretical – Measure expressivity of the language – Formalise currently unspecified aspects – Define security patterns
  29. 29. Conclusion• Security is a cross-cutting concern• Existing AOP point-cuts are not designed for networked systems• A way of relating aspects to distributed systems is needed for security• Propose initial method for defining point-cut patterns