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ACCESS CONTROL: THE NEGLECTED FRONTIER

ACCESS CONTROL: THE NEGLECTED FRONTIER. Ravi Sandhu George Mason University. CONFIDENTIALITY most studied. INTEGRITY less studied. AVAILABILITY least studied. USAGE newest. SECURITY OBJECTIVES. SECURITY TECHNOLOGIES. Access Control Cryptography Audit and Intrusion Detection

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ACCESS CONTROL: THE NEGLECTED FRONTIER

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  1. ACCESS CONTROL: THE NEGLECTED FRONTIER Ravi Sandhu George Mason University

  2. CONFIDENTIALITY most studied INTEGRITY less studied AVAILABILITY least studied USAGE newest SECURITY OBJECTIVES

  3. SECURITY TECHNOLOGIES • Access Control • Cryptography • Audit and Intrusion Detection • Authentication • Assurance • Risk Analysis • .......................

  4. CRYPTOGRAPHY LIMITATIONS • Cryptography cannot protect confidentiality and integrity of • data, keys, software in end systems • Prevent or detect use of covert channels

  5. AUDIT AND INTRUSION DETECTION LIMITATIONS • Intrusion detection cannot by itself • protect audit data and audit collection and analysis software • prevent security breaches • protect against covert channels

  6. ACCESS CONTROL LIMITATIONS • Access control cannot by itself • protect data in transit or storage on an insecure medium • safeguard against misuse by authorized users • protect against covert channels

  7. AUTHENTICATION LIMITATIONS • By itself authentication does very little but what it does is critical • pre-requisite for effective • cryptography • access control • intrusion detection

  8. A MIX OF MUTUALLY SUPPORTIVE TECHNOLOGIES AUTHENTICATION RISK ANALYSIS ASSURANCE ACCESS CONTROL CRYPTOGRAPHY INTRUSION DETECTION SECURITY ENGINEERING & MANAGEMENT

  9. CLASSICAL ACCESS CONTROL DOCTRINE • Lattice-based mandatory access control (MAC) • strong • too strong • not strong enough • Owner-based discretionary access control (DAC) • too weak • too confused

  10. ISSUES IN LATTICE-BASED MAC • MAC enforces one-directional information flow in a lattice of security labels • can be used for aspects of • confidentiality • integrity • aggregation (Chinese Walls)

  11. PROBLEMS WITH LATTICE-BASED MAC • does not protect against covert channels and inference • not strong enough • inappropriate • too strong

  12. ISSUES IN OWNER-BASED DAC • negative “rights” • inheritance of rights • interaction between positive and negative rights • grant flag • delegation of identity • temporal and conditional authorization

  13. PROBLEMS WITH OWNER-BASED DAC • does not control information flow • too weak • inappropriate in many situations • too weak • too confused

  14. BEYOND OWNER-BASED DAC • separation between ability • to use a right • to grant a right • non-discretionary elements • user who can use a right should not be able to grant it and vice versa

  15. NON-DISCRETIONARY (BEYOND LATTICE-BASED MAC) • control of administrative scope • rights that can be granted • to whom rights can be granted • rights that cannot be simultaneously granted to same user • rights that cannot be granted to too many users

  16. WHAT IS THE POLICY IN NON-DISCRETIONARY ACCESS CONTROL? • Non-discretionary access control is a means to articulate policy • does not incorporate policy but does support security principles • least privilege • abstract operations • separation of duties

  17. ISSUES IN NON-DISCRETIONARY ACCESS CONTROL • models for non-discretionary propagation of access rights • role-based access control (RBAC) • task-based authorization (TBA)

  18. NON-DISCRETIONARY PROPAGATION MODELS • HRU, 1976 • TAKE-GRANT, 1976-82 • SPM/ESPM, 1985-92 • TAM/ATAM, 1992 onwards

  19. NON-DISCRETIONARY PROPAGATION MODELS • type-based non-discretionary controls • rights that authorize propagation can be separate or closely related to right being propagated • testing for absence of rights is essential for dynamic separation policies

  20. USER-ROLE ASSIGNMENT PERMISSION-ROLE ASSIGNMENT USERS ROLES PERMISSIONS ... SESSIONS ROLE-BASED ACCESS CONTROL: RBAC0

  21. ... ROLE-BASED ACCESS CONTROL: RBAC1 ROLE HIERARCHIES USER-ROLE ASSIGNMENT PERMISSION-ROLE ASSIGNMENT USERS ROLES PERMISSIONS SESSIONS

  22. HIERARCHICAL ROLES Primary-Care Physician Specialist Physician Physician Health-Care Provider

  23. Supervising Engineer Hardware Engineer Software Engineer Engineer HIERARCHICAL ROLES

  24. ... ROLE-BASED ACCESS CONTROL: RBAC3 ROLE HIERARCHIES USER-ROLE ASSIGNMENT PERMISSIONS-ROLE ASSIGNMENT USERS ROLES PERMISSIONS SESSIONS CONSTRAINTS

  25. ... RBAC MANAGEMENT ROLES PERMISSIONS USERS CAN- MANAGE ADMIN ROLES ADMIN PERMISSIONS

  26. S S3 CSO T5 T2 T4 T1 SO1 SO2 SO3 P3 P ADMINISTRATIVE ROLE HIERARCHY ROLE HIERARCHY RBAC MANAGEMENT

  27. H HR LW LATTICE ROLES L LR HW ROLES AND LATTICES • RBAC can enforce classical lattice-based MAC

  28. H HR LATTICE ROLES HW LW L LR ROLES AND LATTICES • RBAC can accommodate variations of classical lattice-based MAC

  29. TASK-BASED AUTHORIZATION (TBA) • beyond subjects and objects • authorization is in context of some task • transient use-once permissions instead of long-lived use-many-times permissions

  30. TRANSACTION CONTROL EXPRESSIONS (TCEs) • TCEs are an example of TBA • prepare  clerk; approve  supervisor; issue  clerk;

  31. CONCLUSION • access control is important • there are many open issues

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