Domain 3 - Security Models Flashcards
Open/Closed Systems
Closed systems are usually single manufacturer ecosystems, using proprietary standards. Open systems use industry standards, easier to integrate, more widely targeted–distinct from open source
Trusted Computing Base
A combination of hardware, software, and controls that work together to allow a portion of the information system to be trusted to adhere to and enforce the security policy
Security Perimeter
The line between the Trusted Computing Base and the rest of the system. All communications between the two happen along “trusted paths”
Reference Monitor
The part of the Trusted Computing Base that validates access to every resource prior to granting access requests. It is the access enforcer for the TCB
Bell-LaPadula Model
DoD Model from the 70s, with three security properties (simple sec. prop; star sec.prop; discretionary sec. prop).
Only concerned with confidentiality. Built on state machine model and information flow model
Bell-LaPadula Discretionary Security Property
Access is enforced by an access matrix. Enforces subject’s “need to know”
Clark-Wilson Model
“Access Control Triad”, three-part relationship, subject/program/object. Constrained Interface. Focused on integrity
Brewer and Nash Model / Chinese Wall
Access changes dynamically based on a subject’s previous activity, such as that which presents a conflict of interest
Information flow model
Information is restricted to flow in the directions that are permitted by the security policy. Thus flow of information from one security level to another. (Bell & Biba).
Matrix (Access control model)
Provides access rights including discretionary access control to subjects for different objects.
Read, write and execute access defined in ACL as matrix columns and rows as capability lists.
Simple Property
Read. In Biba, no read down. In Bell-LaPadula, no read up
Star Property
Write. In Biba, no write up. In Bell-LaPadula, no write down. Also called confinement property
