Systems Security Certified Practitioner – SSCP – Question0109

Which of the following statements relating to the Bell-LaPadula security model is FALSE (assuming the Strong Star property is not being used) ?

A. A subject is not allowed to read up.
B. The property restriction can be escaped by temporarily downgrading a high level subject.
C. A subject is not allowed to read down.
D. It is restricted to confidentiality.

Correct Answer: C

Explanation:

It is not a property of Bell LaPadula model.
The other answers are incorrect because:
A subject is not allowed to read up is a property of the ‘simple security rule’ of Bell LaPadula model.
The property restriction can be escaped by temporarily downgrading a high level subject can be escaped by temporarily downgrading a high level subject or by identifying a set of trusted objects which are permitted to violate the property as long as it is not in the middle of an operation.
It is restricted to confidentiality as it is a state machine model that enforces the confidentiality aspects of access control. Reference: Shon Harris AIO v3 , Chapter-5 : Security Models and Architecture , Page:279-282