Instant Access ISC.SSCP.v2022-06-29.q999 Actual Practice Test Engine for Free (Page 39)

Question 187

Which of the following statements pertaining to protection rings is false?

A.They provide strict boundaries and definitions on what the processes that work within each ring can access.
B.Programs operating in inner rings are usually referred to as existing in a privileged mode.
C.They support the CIA triad requirements of multitasking operating systems.
D.They provide users with a direct access to peripherals

Correct Answer: D

In computer science, hierarchical protection domains, often called protection rings, are mechanisms to protect data and functionality from faults (fault tolerance) and malicious behaviour (computer security). This approach is diametrically opposite to that of capability-based security.
Computer operating systems provide different levels of access to resources. A protection ring is one of two or more hierarchical levels or layers of privilege within the architecture of a computer system. This is generally hardware-enforced by some CPU architectures that
provide different CPU modes at the hardware or microcode level.
Rings are arranged in a hierarchy from most privileged (most trusted, usually numbered
zero) to least privileged (least trusted, usually with the highest ring number). On most
operating systems, Ring 0 is the level with the most privileges and interacts most directly
with the physical hardware such as the CPU and memory.
Special gates between rings are provided to allow an outer ring to access an inner ring's
resources in a predefined manner, as opposed to allowing arbitrary usage. Correctly gating
access between rings can improve security by preventing programs from one ring or
privilege level from misusing resources intended for programs in another. For example,
spyware running as a user program in Ring 3 should be prevented from turning on a web
camera without informing the user, since hardware access should be a Ring 1 function
reserved for device drivers. Programs such as web browsers running in higher numbered
rings must request access to the network, a resource restricted to a lower numbered ring.
"They provide strict boundaries and definitions on what the processes that work within each
ring can access" is incorrect. This is in fact one of the characteristics of a ring protection
system.
"Programs operating in inner rings are usually referred to as existing in a privileged mode"
is incorrect. This is in fact one of the characteristics of a ring protection system.
"They support the CIA triad requirements of multitasking operating systems" is incorrect.
This is in fact one of the characteristics of a ring protection system.
Reference(s) used for this question:
CBK, pp. 310-311
AIO3, pp. 253-256
AIOv4 Security Architecture and Design (pages 308 - 310)
AIOv5 Security Architecture and Design (pages 309 - 312)

Question 188

Who first described the DoD multilevel military security policy in abstract, formal terms?

A.David Bell and Leonard LaPadula
B.Rivest, Shamir and Adleman
C.Whitfield Diffie and Martin Hellman
D.David Clark and David Wilson

Question 189

Which security model introduces access to objects only through programs?

A.The Biba model
B.The Bell-LaPadula model
C.The Clark-Wilson model
D.The information flow model

Correct Answer: C

Explanation/Reference:
In the Clark-Wilson model, the subject no longer has direct access to objects but instead must access them through programs (well -formed transactions).
The Clark-Wilson integrity model provides a foundation for specifying and analyzing an integrity policy for a computing system.
The model is primarily concerned with formalizing the notion of information integrity. Information integrity is maintained by preventing corruption of data items in a system due to either error or malicious intent. An integrity policy describes how the data items in the system should be kept valid from one state of the system to the next and specifies the capabilities of various principals in the system. The model defines enforcement rules and certification rules.
Clark-Wilson is more clearly applicable to business and industry processes in which the integrity of the information content is paramount at any level of classification.
Integrity goals of Clark-Wilson model:
Prevent unauthorized users from making modification (Only this one is addressed by the Biba model).
Separation of duties prevents authorized users from making improper modifications.
Well formed transactions: maintain internal and external consistency i.e. it is a series of operations that are carried out to transfer the data from one consistent state to the other.
The following are incorrect answers:
The Biba model is incorrect. The Biba model is concerned with integrity and controls access to objects based on a comparison of the security level of the subject to that of the object.
The Bell-LaPdaula model is incorrect. The Bell-LaPaula model is concerned with confidentiality and controls access to objects based on a comparison of the clearence level of the subject to the classification level of the object.
The information flow model is incorrect. The information flow model uses a lattice where objects are labelled with security classes and information can flow either upward or at the same level. It is similar in framework to the Bell-LaPadula model.
References:
ISC2 Official Study Guide, Pages 325 - 327
AIO3, pp. 284 - 287
AIOv4 Security Architecture and Design (pages 338 - 342)
AIOv5 Security Architecture and Design (pages 341 - 344)
Wikipedia at: https://en.wikipedia.org/wiki/Clark-Wilson_model

Question 190

A prolonged power supply that is below normal voltage is a:

A.brownout
B.blackout
C.surge
D.fault

Question 191

Which of the following is NOT an administrative control?

A.Logical access control mechanisms
B.Screening of personnel
C.Development of policies, standards, procedures and guidelines
D.Change control procedures

Question 187

Question 188

Question 189

Question 190

Question 191

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