Domain 3 Flashcards
Threat modeling
- Form of testing
- design to identify critical systems and services
- only identify the problem does not fix it
fail securely
- fail in a secure manner by default
Defense in depth layers
- physical parameter
- perimeter network
- local area network
- host
- applications
- data
Bell- Lapadula (BLP)
- No read Up No write Down
- You can think of a pyramid You can only write stuff at your level or higher and you can read everything at your level and lower - Address confidentiality in a multi level security system
- two security constructs
- subjects and objects - subjects are active parties while objects are the passive parties
- assigned clearances
- early security model does not provide a mechanism for one-to-one mapping of individual subjects and objects
- Defines 3 properties
- simple security property
cannot read or write on the object of Higher classification (no read up)
- star property
a subject with this property can only save an object at the same or higher classification (no write down)
- strong star property
can only write to objects that these same security classification (no write down no write up)
Purpose: Ensures confidentiality by preventing unauthorized data flow.
Key Idea: “No read up, no write down” (focuses on confidentiality).
Mnemonic: “BLP Blocks Leaks” (confidentiality through controlled access).
Biba
- No read down no Write up
- you can think of this as a ladder - addresses integrity but not confidentiality
- Uses observe and modify instead of read and right
- Main difference between Biba and BLP is that it is mostly an integrity model
- Three properties
- simple security property
No read down
- star property
No write up
- invocation property
a subject with a lower integrity level cannot request access to a higher integrity level object only to an object equal or lower integrity level
Biba (Integrity Model)
Purpose: Prevents data from being corrupted by unauthorized or lower integrity data.
Key Idea: “No write up, no read down” (focuses on integrity, opposite of Bell-LaPadula).
Mnemonic: “Biba Boosts Integrity” (protects against corruption).
Brewer and Nash
- Avoid Conflicts Keep context
- Stop shoe from visiting data based off of data already visited
- For example the system remembers your history to enforce restrictions - focuses on preventing conflicts of interest
- principle is that the user should not access confidential information of both the client organization and its competitor
- Access rules change based on subjects behavior
- once you access one party’s information access to the competing organization is automatically revoked
Brewer-Nash (Chinese Wall Model)
Purpose: Prevents conflicts of interest by restricting access based on previously accessed data.
Key Idea: “You can’t access conflicting projects.”
Mnemonic: “Brewer builds Walls” (like the Chinese Wall to separate conflicts of interest).
Clark Wilson
- Well Formed Well checked
- Secure workflow you can think of this as processing a bank withdrawal the system that only allows them to do to do so through a predefined workflow that records the transaction - improvement on the Biba model
- Focuses on integrity at the transaction level
- Requires transactions by authorized subjects to be evaluated by another party providing separation of duties
- Deviation from expected paths or defined steps would result in a failure of the transaction
- establishes a subject program object binding
Clark-Wilson
Purpose: Enforces well-formed transactions and integrity in commercial applications.
Key Idea: Users interact with data only through authorized programs.
Mnemonic: “Clark Cleans Data” (ensures integrity through well-formed transactions).
Graham Denning
- Primarily concerned with how subject and objects are created
- how subjects are assigned rights or privileges
- how ownership of objects is managed - has three parts
- set of subjects
- set of objects
- set of rights - subjects are comprised of two things
- processing a domain - describes 8 primitive protection rates
- create object securely
- Delete objects securely
- create subjects securely
- Delete subjects securely
- provision read access rights securely
- provision grant access right securely
- provision delete access rights securely
- Provision transfer access rights securely
Graham-Denning
Purpose: Describes how subjects and objects are created, deleted, and managed in systems.
Key Idea: Set of 8 rules for managing subjects, objects, and rights.
Mnemonic: “Graham Grants Rights” (emphasizes management of access rights).
Harrison, Ruzzo, Ullman (HRU)
- Modify Access maintain Control
- Similar to the graham denning model
- also concerned with subject being restricted from gaining particular privileges
Purpose: General framework for access control in systems, focuses on access rights.
Key Idea: Tracks creation, deletion, and transfer of rights.
Mnemonic: “HRU Handles Rights Universally” (models access control flexibly).
Common selected security standards
- INCOSE Systems engineering handbook
- NIST SP800-160 system security engineering
- ISO/IEC 15026 series systems and software engineering
- ISO/IEC/IEEE 15288 systems and software engineering
INCOSE Systems engineering handbook
- Not-for-profit member organization
- present system principles in terms of affordability and performance
NIST SP800-160 system security engineering
- Addresses the engineering driven actions
- starts with a well established international standards for systems and software engineering by ISO and IEEE and infuses system security engineering techniques methods and practices
ISO/IEC 15026 series systems and software engineering
- Focuses on system and software engineering
ISO/IEC/IEEE 15288 systems and software engineering
- overall system engineering lifecycle model
- outgrowth of earlier models and various military standards and specifications
Technical management process
- (P) project planning
- (A) project assessment and control
- (D) decision making process
- (R) risk management process
- (C) configuration and management process
- (I) information management process
- (M) measurement process
- (Q) quality assurance process
- Please Ask Don’t Risk completely ignoring management Quality
