1. Access Control What’s New?

2. Security Controls Access Control Inference Control Flow control
CSCE Farkas

3. Access Control
Protection objects: system resources for which protection is desirable
Memory, file, directory, hardware resource, software resources, etc.
Subjects: active entities requesting accesses to resources
User, owner, program, etc.
Access mode: type of access
Read, write, execute
CSCE Farkas

4. Access Control Requirement
Cannot be bypassed
Enforce least-privilege and need-to-know restrictions
Enforce organizational policy
Theoretical Properties:
Consistent
Complete
CSCE Farkas

5. Access Control
Access control: ensures that all direct accesses to object are authorized
Protects against accidental and malicious threats by regulating the reading, writing and execution of data and programs
Need:
Proper user identification and authentication
Information specifying the access rights is protected form modification
CSCE Farkas

6. Access Control Overview
Access control components:
Access control policy: specifies the authorized accesses of a system
Access control mechanism: implements and enforces the policy
Separation of components allows to:
Define access requirements independently from implementation
Compare different policies
Implement mechanisms that can enforce a wide range of policies
CSCE Farkas

7. Closed v.s. Open Systems Closed system Open System yes no no yes
(minimum privilege)
(maximum privilege)
Access requ.
Access requ.
Allowed
accesses
Disallowed
accesses
Exists Rule?
Exists Rule?
yes no no
yes
Access
permitted
Access
denied
Access
permitted
Access
denied
CSCE Farkas

8. Access Control Models Discretionary Access Control
Mandatory Access Control
Role-Based Access Control
Attribute-based Access Control
Usage-based Access Control
Context-based Access Control …
CSCE Farkas

9. Policy Compliance
How can we model both high-level and low-level security policies in one framework?
How can we determine whether the low-level policy and current system configuration is compliant to the high-level policy?

10. Compliance Checking Framework
High-level policy 1
Detect Conflicts and Violations 4 6
Report
Refinement 2 3 5 5
KB – Ontology and
Refinement Patterns
(Concept-level):
Common to all
Domain-specific
Domain-data (Instance):
System configuration,
Low-level security policies
Domain-data (Instance):
Role-assignment,
Organization structure

11. What else? Go from binary decision to …maybe? Delegation ???
Provisional Access Control
Obligation
Delegation
???
CSCE Farkas

12. Next Class
Inference Control
CSCE Farkas