- (Topic 2)
What can best be described as an abstract machine which must mediate all access to subjects to objects?

Correct Answer:B
The reference monitor is an abstract machine which must mediate all access to subjects to objects, be protected from modification, be verifiable as correct, and is
always invoked. The security kernel is the hardware, firmware and software elements of a trusted computing base that implement the reference monitor concept. The security perimeter includes the security kernel as well as other security-related system functions that are within the boundary of the trusted computing base. System elements that are outside of the security perimeter need not be trusted. A security domain is a domain of trust that shares a single security policy and single management.
Source: TIPTON, Hal, (ISC)2, Introduction to the CISSP Exam presentation.

- (Topic 5)
What is the name of the third party authority that vouches for the binding between the data items in a digital certificate?

Correct Answer:B
A certification authority (CA) is a third party entity that issues digital certificates (especially X.509 certificates) and vouches for the binding between the data items in a certificate. An issuing authority could be considered a correct answer, but not the best answer, since it is too generic.
Source: SHIREY, Robert W., RFC2828: Internet Security Glossary, may 2000.

- (Topic 5)
Which of the following is not a disadvantage of symmetric cryptography when compared
with Asymmetric Ciphers?

Correct Answer:C
Symmetric cryptography ciphers are generally fast and hard to break. So speed is one of the key advantage of Symmetric ciphers and NOT a disadvantage. Symmetric Ciphers uses simple encryption steps such as XOR, substitution, permutation, shifting columns, shifting rows, etc... Such steps does not required a large amount of processing power compare to the complex mathematical problem used within Asymmetric Ciphers.
Some of the weaknesses of Symmetric Ciphers are:
The lack of automated key distribution. Usually an Asymmetric cipher would be use to protect the symmetric key if it needs to be communicated to another entity securely over a public network. In the good old day this was done manually where it was distributed using the Floppy Net sometimes called the Sneaker Net (you run to someone's office to give them the key).
As far as the total number of keys are required to communicate securely between a large group of users, it does not scale very well. 10 users would require 45 keys for them to communicate securely with each other. If you have 1000 users then you would need almost half a million key to communicate secure. On Asymmetric ciphers there is only 2000 keys required for 1000 users. The formula to calculate the total number of keys required for a group of users who wishes to communicate securely with each others using Symmetric encryption is Total Number of Users (N) * Total Number of users minus one Divided by 2 or N (N-1)/2
Symmetric Ciphers are limited when it comes to security services, they cannot provide all of the security services provided by Asymmetric ciphers. Symmetric ciphers provides mostly confidentiality but can also provide integrity and authentication if a Message Authentication Code (MAC) is used and could also provide user authentication if Kerberos is used for example. Symmetric Ciphers cannot provide Digital Signature and Non- Repudiation.
Reference used for theis question:
WALLHOFF, John, CBK#5 Cryptography (CISSP Study Guide), April 2002 (page 2).

- (Topic 1)
Which of the following is NOT an advantage that TACACS+ has over TACACS?

Correct Answer:A
Although TACACS+ provides better audit trails, event logging is a service that is provided with TACACS.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 3: Telecommunications and Network Security (page 121).

- (Topic 4)
The typical computer fraudsters are usually persons with which of the following characteristics?

Correct Answer:C
These people, as employees, are trusted to perform their duties honestly and not take advantage of the trust placed in them.
The following answers are incorrect:
They have had previous contact with law enforcement. Is incorrect because most often it is a person that holds a position of trust and this answer implies they have a criminal background. This type of individual is typically not in a position of trust within an organization.
They conspire with others. Is incorrect because they typically work alone, often as a form of retribution over a percieved injustice done to them.
They deviate from the accepted norms of society. Is incorrect because while the nature of fraudsters deviate from the norm, the fraudsters often hold a position of trust within the organization.

- (Topic 2)
A channel within a computer system or network that is designed for the authorized transfer of information is identified as a(n)?

Correct Answer:B
An overt channel is a path within a computer system or network that is designed for the authorized transfer of data. The opposite would be a covert channel which is an unauthorized path.
A covert channel is a way for an entity to receive information in an unauthorized manner. It is an information flow that is not controlled by a security mechanism. This type of information path was not developed for communication; thus, the system does not properly protect this path, because the developers never envisioned information being passed in this way. Receiving information in this manner clearly violates the system??s security policy.
All of the other choices are bogus detractors. Reference(s) used for this question:
KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten
Domains of Computer Security, 2001, John Wiley & Sons, Page 219. and
Shon Harris, CISSP All In One (AIO), 6th Edition , page 380 and
Harris, Shon (2012-10-25). CISSP All-in-One Exam Guide, 6th Edition (p. 378). McGraw- Hill. Kindle Edition.