ISC2 CISSP (Certified Information Systems Security Professional)Security Architecture and EngineeringMedium
A security architect is designing a new system that will handle sensitive government intelligence. The primary requirement is to prevent information from flowing from a higher security level to a lower security level, even if the user has clearance for both. Which security model is best suited to enforce this specific confidentiality requirement?
- ABell-LaPadula Security Model
- BClark-Wilson Security Model
- CBrewer-Nash (Chinese Wall) Model
- DBiba Security Model
Show answer & explanationAnswer & explanation
Correct answer: A. Bell-LaPadula Security Model
The Bell-LaPadula Security Model is specifically designed to enforce confidentiality by preventing information flow from higher security levels to lower security levels, adhering to the 'no write-down' rule. This aligns perfectly with the requirement to protect sensitive government intelligence.
Why the other options are wrong
- B. The Clark-Wilson model focuses on integrity, specifically preventing unauthorized modification of data through well-formed transactions.
- C. The Brewer-Nash model prevents conflicts of interest, ensuring that a user cannot access information from competing companies.
- D. The Biba model focuses on integrity, preventing information flow from lower integrity levels to higher integrity levels.
Bell-LaPadula Security Model
A state-machine model focused on enforcing confidentiality by preventing unauthorized access to classified information.
- Primarily concerned with confidentiality.
- Uses 'no read-up' and 'no write-down' rules.
- Commonly applied in military and government systems.
Memory trick: Confidential Bell rings for secret government documents.