SSCP Systems Security Certified PractitionerAccess ControlsMedium
A system architect is designing an access control system for a highly sensitive research laboratory. The policy prohibits any subject from writing to an object at a lower security level (no write-down) and also prevents reading from an object at a higher security level (no read-up). This design is intended to prevent information flow from higher to lower sensitivity levels. Which specific access control model property is being implemented?
- ABiba integrity model
- BBell-LaPadula model
- CSimple Security Property (no read-up)
- D*-Property (Star Property) (no write-down)
Show answer & explanationAnswer & explanation
Correct answer: B. Bell-LaPadula model
The Bell-LaPadula model is a state machine security model that enforces confidentiality. It has two main properties: the Simple Security Property (no read-up) and the *-Property (Star Property) (no write-down). The scenario explicitly describes both of these properties, indicating the implementation of the Bell-LaPadula model.
Why the other options are wrong
- A. The Biba model focuses on integrity, preventing write-up and read-down, which is the opposite of the described confidentiality goals.
- C. This is only one part of the described properties, not the complete model.
- D. This is only one part of the described properties, not the complete model.
Bell-LaPadula Model
A state machine model used for enforcing confidentiality, specifically designed to prevent unauthorized disclosure of information.
- Focuses on confidentiality.
- Uses security levels (e.g., Top Secret, Secret, Confidential).
- Comprises Simple Security Property (no read-up) and *-Property (no write-down).
Memory trick: Bell-LaPadula rings the alarm against info leaks: NO Read-Up, NO Write-Down!