ISC Exam Questions

Which of the following security models does NOT concern…

Which of the following security models does NOT concern itself with the flow of data?

A.
The information flow model

B.
The Biba model

C.
The Bell-LaPadula model

D.
The noninterference model

Explanation:
Multilevel security properties can be expressed in many ways, one being noninterference. This concept is
implemented to ensure any actions that take place at a higher security level do not affect, or interfere with,
actions that take place at a lower level. This type of model does not concern itself with the flow of data,
but rather with what a subject knows about the state of the system. So if an entity at a higher security level
performs an action, it cannot change the state for the entity at the lower level.
If a lower-level entity was aware of a certain activity that took place by an entity at a higher level and the state of
the system changed for this lower-level entity, the entity might be able to deduce too much information about
the activities of the higher state, which in turn is a way of leaking information. Users at a lower security level
should not be aware of the commands executed by users at a higher level and should not be affected by those
commands in any way.
Incorrect Answers:
A: The information flow model does concern itself with the flow of data.
B: The Biba model does concern itself with the flow of data.
C: The Bell-LaPadula model does concern itself with the flow of data.

Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, New York, 2013, p. 380