Computer Security: Chapter 7 - Using Trust for Role-Based Access Control (RBAC)

7. Using Trust for Role-BasedAccess Control (RBAC) Prof. Bharat Bhargava Center for Education and Research in Information Assurance and Security (CERIAS) and Department of Computer Sciences Purdue University http://www.cs.purdue.edu/people/bb bb@cs.purdue.edu Collaborators in the RAID Lab (http://raidlab.cs.purdue.edu): Prof. Leszek Lilien (former Post Doc) Dr. Yuhui Zhong (former Ph.D. Student) This research is supported by CERIAS and NSF grants from IIS and ANIR. 1 --- 12/11/15 11:45 AM Using Trust for Role­Based Access Control ­ Outline 1) Access Control in Open Systems 2) Proposed Access Control Architecture 2.1) Basics 2.2) RBAC & TERM server 3) TERM server 3.1) Basic 3.2) Evidence Model 3.3) Architecture a) Credential Management (CM) b) Evidence Evaluation (EE) c) Role Assignment (RA) d) Trust Information Management (TIM) 3.4) Prototype TERM server 2 --- 12/11/15 11:45 AM 1) Access Control in Open Systems (1) Open environment (like WWW, WiFi networks) User who may not be known in advance Still must determine the permission set for an unknown user Common approach: Grant access based on user’s properties demonstrated by digital credentials Problems with credentials Holding credentials does not assure user trustworthiness Evidence provided by different credential issuers should not be uniformly trusted (apply “degrees of trust”) 3 --- 12/11/15 11:45 AM 1) Access Control in Open Systems (2) A solution for problems with credentials: Trust should be used by access control mechanisms To limit granting privileges to potentially harmful users How to establish trust ? In particular with “newcomer” devices What do we need to know about a pervasive device, in order to make a trust decision? Using trust for attribute-based access control Identity-based access control is inadequate in open environments (e.g., vulnerable to masquerading) Multi-dimensional attribute set to determine trust level 4 --- 12/11/15 11:45 AM 2.1) Proposed Access Control Architecture - Basics Authorized Users Other Users Access Control Mechanism Information System Authorized Users Validated credentials (first-hand experience and second-hand recommendations) AND Trust based on history of cooperative and legitimate behavior Other Users Lack of required credentials OR Lack of trust resulting from history of non-cooperative or malicious behavior 5 --- 12/11/15 11:45 AM ... - tailieumienphi.vn