semi-automated modelling of XACML policies

1. semi-automated modelling of XACML policies Simon ParkinAad van Moorsel Newcastle University

2. setting Chief Information Security Officer (CISO) must continuously make IT investment decision should take into account: • technology • business priorities and impact • employee reaction and impact tools to help CISO  trust economics (HP, ML) Aad van Moorsel, Newcastle University, DTI Trust Economics

3. trust economics tools Aad van Moorsel, Newcastle University, DTI Trust Economics

4. knowledge base and policies knowledge base: • existing base of policies, guidelines, e.g., ISO27k • add ontology for user behaviour, trade-offs, etc. • add calculators, models as appropriate • helps CISO to take into account the major elements when making decision interface to knowledge base through security policies: set of rules fed into knowledge base  if I do X, what happens and what else should I do? Aad van Moorsel, Newcastle University, DTI Trust Economics

5. knowledge base and policies knowledge base (for integration) policies (to express decisions,interface with kb) Aad van Moorsel, Newcastle University, DTI Trust Economics

6. prototype: XACML Policy Editor Aad van Moorsel, Newcastle University, DTI Trust Economics

7. a prototype: XACML + Demos2K • IT Security officer uses XACML editor to write policies • tool feeds the policies in Demos2K (stochastic process algebra specification, solved using discrete-event simulation) • tool returns outcomes: loss of data, confidentiality, productivity, ... XACML • eXtensible Access Control Markup Language • OASIS standard • policy language + specified interpretation Aad van Moorsel, Newcastle University, DTI Trust Economics

8. a prototype: XACML + Demos2K demos2k XACML Aad van Moorsel, Newcastle University, DTI Trust Economics

9. a prototype: XACML + Demos2K demos2k Aad van Moorsel, Newcastle University, DTI Trust Economics

10. Aad van Moorsel, Newcastle University, DTI Trust Economics

11. USB stick modelling Aad van Moorsel, Newcastle University, DTI Trust Economics

12. day in the life of a USB stick Aad van Moorsel, Newcastle University, DTI Trust Economics

13. USB roles Aad van Moorsel, Newcastle University, DTI Trust Economics

14. USB locations Aad van Moorsel, Newcastle University, DTI Trust Economics

15. example demos2k // Here both the FRIEND and TRAITOR cases are taken as being very similar - after all the // TRAITOR player is supposed to be indistinguishable to the FRIEND - and thus the // accounting should treat them broadly the same way. etry [who == player__FRIEND || who == player__TRAITOR] then { try [ binom(1, prob_reading_unencrypted_item) == 1 ] then { // unencrypted case successful_reads := successful_reads + 1; successful_transfers := successful_transfers + 1; // accidental archive of accessable material - i.e. USB_unencrypted_items try [binom(1, probAccidentalArchive) == 1] then { syncV(USBreveal, [USB_unencrypted_items], []); } etry [] then { hold(0); } // if player is actually a TRAITOR try [who == player__TRAITOR] then { Aad van Moorsel, Newcastle University, DTI Trust Economics

16. goals Aad van Moorsel, Newcastle University, DTI Trust Economics

17. experiments Aad van Moorsel, Newcastle University, DTI Trust Economics

18. Aad van Moorsel, Newcastle University, DTI Trust Economics

19. Aad van Moorsel, Newcastle University, DTI Trust Economics

20. evaluation XACML + Demos2K • prototype works (XACML as input to a stochastic model) to do: • formalise this • generalise this • is a policy language the right interface? • CISOs don’t normally use it • flexible enough as interface to knowledge base Aad van Moorsel, Newcastle University, DTI Trust Economics