Architectures and Models for Administration of User-Role Assignment in Role Based Access Control

1. PhD Dissertation Architectures and Models for Administration of User-Role Assignment in Role Based Access Control Venkata Bhamidipati

2. Presentation Outline • Introduction • Decentralized user-role assignment (URA97) • ASCAA principles • Self service role assignment (SSRBAC08) • Conclusions • Contributions • Future work • Publications 2 Venkata Bhamidipati

3. Introduction • Principal motivation of RBAC is to simplify administration. • Using RBAC to manage itself is an appealing possibility • Three components in administration of RBAC • user–role, permission–role, role-role • Focus of this work is on user-role administration 3 Venkata Bhamidipati

4. Introduction: Problem Statement • In large systems administration is a big task. • Frequent changes to • user-role assignment • roles: 100s or 1000s • users: 1000s or 10,000s or more • Less frequent changes for • role hierarchy • Need for decentralization and automation of user-role assignment • Early Part of this work focuses on decentralization (URA97). Later part on automation (SSRBAC08) 4 Venkata Bhamidipati

5. Introduction: Contributions • URA97 model for user role assignment • Related work: Munawer 99, Oh 2002 • PRA97 for permission role assignment • URA97 proof of concept implementation in Oracle • Related work: Ahn & Sandhu 98,01 Sandhu & Park 98 • Push model for user assignment in distributed systems • Related work: Dekker 2008 • ASCAA principles for next generation RBAC • Framework for self service assignment (SSRBAC08) • Related work: Khatani 2004 5 Venkata Bhamidipati

6. ROLES PERMISSIONS USERS Constraints ... Sessions ADMIN ROLES ADMIN PERMISSIONS Introduction: RBAC96 SSRBAC08 URA97 6 Venkata Bhamidipati

7. Introduction: OM-AM Decentralization and Automation URA97, PRA97, SSRBAC08 Push Model for URA97 Oracle Stored Procedures 7 Venkata Bhamidipati

8. User Role Assignment (URA97) • Model to administer user-role assignment • Decentralizes user-role administration • Members of administrative roles perform assignment and revocation operations 8 Venkata Bhamidipati

9. Director (DIR) Project Lead 1 (PL1) Project Lead 2 (PL2) Production 1 (P1) Quality 1 (Q1) Production 2 (P2) Quality 2 (Q2) Engineer 1 (E1) Engineer 2 (E2) Engineering Department (ED) PROJECT 1 PROJECT 2 Employee (E) Example Role Hierarchy 9 Venkata Bhamidipati

10. Example Administrative Role Hierarchy Senior Security Officer (SSO) Department Security Officer (DSO) Project Security Officer 1 (PSO1) Project Security Officer 2 (PSO2) 10 Venkata Bhamidipati

11. URA97 Grant Model: can-assign • Imposes restrictions on which users can be added to a role by whom • The can-assign relation • can-assign (x,y,{a,b,c}) • a member of administrative role x (or senior to x) can assign a user whose current membership, or non-membership, in regular roles satisfies the prerequisite condition y to be a member of regular roles a, b or c • The prerequisite condition is a boolean expression on terms of the form z(u) where z(u) is a boolean function with the same name as role z which evaluates to true if user u is a member of role z and evaluates to false otherwise 11 Venkata Bhamidipati

12. URA97 Grant Model : can-assign • Alice is a member of admin role PSO1 • She can assign a user regular role E1, if the user satisfies condition of having membership in role ED • She can assign a user regular role Q1, if the user satisfies condition of having membership in ED and not having P1 • She can assign a user regular role PL1, if the user satisfies condition of having membership in P1 and Q1 • Bob is a member of admin role DSO • He can assign a user regular roles in the range (ED, DIR), if the user satisfies condition of having membership in role ED 12 Venkata Bhamidipati

13. URA97 Grant Model • “redundant” assignments to senior and junior roles • are allowed • are useful 13 Venkata Bhamidipati

14. URA97 Revoke Model : can-revoke • The can-revoke relation • can-revoke (x,Y), when Y: range of revocation. a member of the administrative role x (or senior to x) can revoke membership of a user from any regular role yY. • Weak revocation • revokes explicit membership in a role • independent of who did the assignment • Strong Revocation • revokes explicit membership in a role and its seniors • authorized only if corresponding weak revokes are authorized • alternatives • all-or-nothing, revoke within range 14 Venkata Bhamidipati

15. ARole Role Range PSO1 [E1,PL1) PSO2 [E2,PL2) DSO (ED,DIR) SSO [ED,DIR] URA97 Revoke Model : can-revoke 15 Venkata Bhamidipati

16. Introduction: Contributions • URA97 model for user role assignment • Related work: Munawer 99, Oh 2002 • PRA97 for permission role assignment • URA97 proof of concept implementation in Oracle • Related work: Ahn & Sandhu 98,01 Sandhu & Park 98 • Push model for user assignment in distributed systems • Related work: Dekker 2008 • ASCAA principles for next generation RBAC • Framework for self service assignment (SSRBAC08) • Related work: Al-Khatani 2004 16 Venkata Bhamidipati

17. ASCAA Principles • RBAC96 based on four foundation principles • Abstraction of privileges • Separation of administrative functions • Least privilege • Separation of duty • Manual intervention in RBAC administration is cumbersome • New concepts like usage control, rate limits have gained traction • Accountability is receiving renewed interest 17 Venkata Bhamidipati

18. ASCAA Principles Abstraction • Remains unchanged from RBAC96 Separation of Administrative functions • Remains unchanged from RBAC96 Containment • Subsumes least privilege, separation of duties • Includes usage control, rate limits Automation • Assignment, revocation Accountability • Re-authentication, obligations, notification and alerts 18 Venkata Bhamidipati

19. Self Service User Assignment (SSRBAC08) • URA97 requires administrative effort • Simplify administration • A framework for self service user assignment • Based on ASCAA principles 19 Venkata Bhamidipati

20. SSRBAC08 contd.. • Modifies RBAC96 • Constraints are classified into four categories • Assignment Criteria • Administrative Criteria • Usage Criteria • Revocation Criteria • Role attributes hold criteria 20 Venkata Bhamidipati

21. SSRBAC08 contd.. SSRBAC08 Framework 21 Venkata Bhamidipati

22. SSRBAC08 contd.. • Assignment Criteria (AC) • Defines criteria that need to be satisfied by assignee for role assignment • Example criteria include • membership or non membership in roles, approvals, obligations, cardinality limits, rate limits • Administrative Criteria (ADC) • Defines criteria that control administrative functions • Example criteria include • people who are allowed to grant the role, specify if self assignment is allowed, rate limits, approvals, obligations 22 Venkata Bhamidipati

23. SSRBAC08 contd.. • Usage Criteria (UC) • Defines criteria that control role usage • Example criteria include • environmental conditions, temporal limits, rate limits, dynamic separation of duties, cardinality limits, approvals , obligations • Revocation Criteria (RC) • Defines criteria that control role revocation • Example criteria include • role expiration and time limits, approvals, obligations 23 Venkata Bhamidipati

24. Example Hierarchy 24 Venkata Bhamidipati

25. SSRBAC08 Example ADC for Role E1 1. Users who have consultant role can perform self assignment. 2. Members with PL1 or higher role can assign E1 role to others. 3. Only 2 assignments in a day can be made by members of roles junior to Eng VP role. 4. No more than 20 assignments of this role per week. 5. There is a cardinality limit of 30 members for users with consultant role. 6. To override cardinality rule need an approval from Eng VP. 7. Members with Dir or higher can perform revocation. AC for Role E1 1. Assignee should have role EMP and not belong to E2. 2. Approval of Dir or higher needed to override prerequisite condition. 3. Assignee should not have exceeded 5 self assignment operations in the current month. 4. Obligation to complete mandatory system training 5 days from assignment. 25 Venkata Bhamidipati

26. SSRBAC08 Example UC for Role E1 1. Cannot activate if E2 is active. 2. Extranet activation allowed if role C is active. 3. Activation of role allowed from extranet only during 9 AM-5 PM Mon-Fri. RC for Role E1 1. Revoke if assignment obligations are not met. 2. Revoked 1 year from assignment date. 3. Need extension approval from Dir or above to override 1 year rule. 4. Revocation if no activation in 3 months period. 5. Self revoke requires Dir approval. 26 Venkata Bhamidipati

27. Role ADC AC ED Assignor needs to have SSO Assignee needs to have E E1 Assignor needs to have PSO1 or senior Assignee needs to have ED PE1 Assignor needs to have PSO1 or senior If assignor is PSO1 then assignee should have ED and not have QE1. If assignor is DSO or higher then assignee should have ED. QE1 Assignor needs to have PSO1 or senior If assignor is PSO1 then assignee should have ED and not have PE1. If assignor is DSO or higher then assignee should have ED. PL1 Assignor needs to have PSO1 or senior If assignor is PSO1 then assignee should have QE1 and PE1. If assignor is DSO or higher then assignee should have ED. DIR Assignor needs to have SSO Assignee needs to have ED URA97 in SSRBAC08 Prerequisite Conditions 27 Venkata Bhamidipati

28. Role ADC ED SSO or higher can revoke E1 PSO1 or higher can revoke PE1 PSO1 or higher can revoke QE1 PSO1 or higher can revoke E2 PSO2 or Higher can revoke PE2 PSO2 or higher can revoke QE2 PSO2 or higher can revoke PL1 DSO or higher can revoke PL2 DSO or higher can revoke DIR SSO or higher can revoke URA97 in SSRBAC08 Revocation 28 Venkata Bhamidipati

29. Conclusions • RBAC can be used to manage itself • URA97 model allows to decentralize user-role assignment • URA97 is viable • Proof of concept implementation in Oracle • SSRBAC08 framework allows to realize self service assignment • Related Work • URA97 Implementations on other platforms (Nt, Unix, and Web) • URA02 • Attributed Based RBAC 29 Venkata Bhamidipati

30. Contributions • URA97 • One of the earliest RBAC administrative model • Decentralizes User-Roles Assignment • Needs Administrative roles. • PRA97 • Dual of URA97 • Decentralizes permission-Role Assignment • Implemented URA97 in Oracle • Proof of concept implementation 30 Venkata Bhamidipati

31. Contributions • Push Model • Deals with User-role assignment in distributed systems. • Global hierarchy is maintained in a centralized location • Pushes assignment and revocation information to local systems • ASCAA Principles • Extend RBAC foundation principles • Containment includes SOD, least privilege and usage control • Automation and accountability are introduced 31 Venkata Bhamidipati

32. Contributions • SSRBAC08 • Framework for self service user-role assignment built on ASCAA principles. • Modifies RBAC96 by classifying constraints into four categories • Assignment and Administrative Criteria determine assignment policy • Usage Criteria determines usage policy • Revocation and Administrative Criteria determine Revocation policy 32 Venkata Bhamidipati

33. Future Work • Policy Language for SSRBAC08 criteria • Extend Attribute based RBAC to use • How to model RORBAC in SSRBAC08 framework 33 Venkata Bhamidipati

34. Publications • Ravi Sandhu and Venkata Bhamidipati, "The URA97 Model for Role-Based User-Role Assignment", IFIP11.3 1997. • Ravi Sandhu, Venkata Bhamidipati, Edward Coyne, Srinivas Ganta and Charles Youman, "The ARBAC97 Model for Role-Based Administration of Roles: Preliminary Description and Outline", ACM RBAC 1997 • Ravi Sandhu and Venkata Bhamidipati, "An Oracle Implementation of the PRA97 Model for Permission-Role Assignment", ACM RBAC 1998. • Ravi Sandhu, Venkata Bhamidipati and Qamar Munawer, "The ARBAC97 Model for Role-Based Administration of Roles", ACM Transactions on Information and Systems Security (TISSEC), Volume 2, Number, February 1999. • Ravi Sandhu and Venkata Bhamidipati, "Role-Based Administration of User-Role Assignment: The URA97 Model and its Oracle Implementation", Journal of Computer Security, Volume 7, 1999. • Venkata Bhamidipati and Ravi Sandhu, "Push Architectures for User-Role Assignment", NISSC 2000. • Ravi Sandhu and Venkata Bhamidipati, "The ASCAA Principles for Next-Generation Role-Based Access Control". Proc. 3rd International Conference on Availability, Reliability and Security (ARES), 2008 34 Venkata Bhamidipati