Security Models

Question 1

Key features of Bell-LaPadula

Answer 1

Focuses on Confidentiality
Is Mandatory
Access Tuple Subject-Object
Is Lattice-Based
Relies on State Machine
Is an Information Flow Model

Simple Security Property: NO READ UP
* Security Property: NO WRITE DOWN
Discretionary Security Property

DOES NOT ADDRESS “NEED TO KNOW”

Question 2

Features of Biba

Answer 2

Focuses on Integrity
Is Mandatory
Access Tuple Subject-Object
Is Lattice-Based
Relies on State Machine
Is an Information Flow Model

Simple Integrity Property: NO READ DOWN
* Integrity Property: NO WRITE UP

FIRST GOAL OF INTEGRITY
-Prevent data modification by unauthorized parties

Question 3

Features of Clark-Wilson

Answer 3

Focuses on Integrity
Is Discretionary
Access Triple Subject-Program-Object
NOT Lattice-Based
DOES NOT Rely on State Machine
Is NOT an Information Flow Model

Well-formed transactions
Separation of duties

ALL THREE GOALS OF INTEGRITY

• Prevent data modification by unauthorized parties
• Prevent unauthorized data modification by authorized parties
• Maintain internal and external consistency (i.e. data reflects the real world)

Question 4

Features of Brewer and Nash

Answer 4

Focuses on Confidentiality
Is Discretionary
Access Tuple Subject-Object
NOT Lattice-Based
DOES NOT Rely on State Machine
Is an Information Flow Model

Chinese wall
Mutual exclusivity
Prevent conflict of interest

Question 5

Features of Goguen-Meseguer

Answer 5

Focuses on Integrity
Noninterference model
Based on predetermining the set or domain - the list of objects that a subject can access
Subjects are unable to interfere with each other’s activities

Question 6

Features of Sutherland

Answer 6

Focuses on Integrity
Prevents interference
Relies on Formal State Machine
Is an Information Flow Model

Defines:

• System states
• Initial states
• State transitions

Prevents use of covert channels

Question 7

Features of Graham-Denning

Answer 7

Focuses on secure creation and deletion of subjects and objects

8 primary protection rules:

1. Securely create an object
2. Securely create a subject
3. Securely delete an object
4. Securely delete a subject
5. Securely provide the read access right
6. Securely provide the grant access right
7. Securely provide the delete access right
8. Securely provide the transfer access right