Which of the following refers to the data left on the media after the media has been erased?
Correct Answer: A
Actually the term "remanence" comes from electromagnetism, the study of the electromagnetics. Originally referred to (and still does in that field of study) the magnetic flux that remains in a magnetic circuit after an applied magnetomotive force has been removed. Absolutely no way a candidate will see anywhere near that much detail on any similar CISSP question, but having read this, a candidate won't be likely to forget it either. It is becoming increasingly commonplace for people to buy used computer equipment, such as a hard drive, or router, and find information on the device left there by the previous owner; information they thought had been deleted. This is a classic example of data remanence: the remains of partial or even the entire data set of digital information. Normally, this refers to the data that remain on media after they are written over or degaussed. Data remanence is most common in storage systems but can also occur in memory. Specialized hardware devices known as degaussers can be used to erase data saved to magnetic media. The measure of the amount of energy needed to reduce the magnetic field on the media to zero is known as coercivity. It is important to make sure that the coercivity of the degausser is of sufficient strength to meet object reuse requirements when erasing data. If a degausser is used with insufficient coercivity, then a remanence of the data will exist. Remanence is the measure of the existing magnetic field on the media; it is the residue that remains after an object is degaussed or written over. Data is still recoverable even when the remanence is small. While data remanence exists, there is no assurance of safe object reuse. Reference(s) used for this question: Hernandez CISSP, Steven (2012-12-21). Official (ISC)2 Guide to the CISSP CBK, Third Edition ((ISC)2 Press) (Kindle Locations 4207-4210). Auerbach Publications. Kindle Edition. and Hernandez CISSP, Steven (2012-12-21). Official (ISC)2 Guide to the CISSP CBK, Third Edition ((ISC)2 Press) (Kindle Locations 19694-19699). Auerbach Publications. Kindle Edition.
Question 603
Which of the following is an advantage that UDP has over TCP?
Correct Answer: C
UDP is a scaled-down version of TCP. It is used like TCP, but only offers a "best effort" delivery. It is connectionless, does not offer error correction, does not sequence the packet segments, and less reliable than TCP but because of its lower overhead, it provides a faster transmission than TCP. 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 86).
Question 604
Password crackers fall into two broad categories. What are they?<br>(Choose two)
Correct Answer: A,E
Password crackers are programs that circumvent password security by revealing passwords that have previously been encrypted. These systems work by using dictionary attacks or brute force.
Question 605
Who developed one of the first mathematical models of a multilevel-security computer system?
Correct Answer: C
Explanation/Reference: In 1973 Bell and LaPadula created the first mathematical model of a multi-level security system. The following answers are incorrect: Diffie and Hellman. This is incorrect because Diffie and Hellman was involved with cryptography. Clark and Wilson. This is incorrect because Bell and LaPadula was the first model. The Clark-Wilson model came later, 1987. Gasser and Lipner. This is incorrect, it is a distractor. Bell and LaPadula was the first model.
Question 606
What is the primary goal of setting up a honeypot?
Correct Answer: D
The primary purpose of a honeypot is to study the attack methods of an attacker for the purposes of understanding their methods and improving defenses. "To lure hackers into attacking unused systems" is incorrect. Honeypots can serve as decoys but their primary purpose is to study the behaviors of attackers. "To entrap and track down possible hackers" is incorrect. There are a host of legal issues around enticement vs entrapment but a good general rule is that entrapment is generally prohibited and evidence gathered in a scenario that could be considered as "entrapping" an attacker would not be admissible in a court of law. "To set up a sacrificial lamb on the network" is incorrect. While a honeypot is a sort of sacrificial lamb and may attract attacks that might have been directed against production systems, its real purpose is to study the methods of attackers with the goals of better understanding and improving network defenses. References AIO3, p. 213
