Analyzing resources of a system is one standard for locating covert channels because the basis of a covert channel is a shared resource.
The following properties must hold for a storage channel to exist:
1. Both sending and receiving process must have access to the same attribute of a shared object.
2. The sending process must be able to modify the attribute of the shared object.
3. The receiving process must be able to reference that attribute of the shared object.
4. A mechanism for initiating both processes and properly sequencing their respective accesses to the shared resource must exist.
Note: Similar properties for timing channel can be listed
The following answers are incorrect:
All other answers were not directly related to discovery of Covert Channels.
The following reference(s) were/was used to create this question:
Auerbach Publications, Auerbach Publications (Test Series) - CRC Press LLC, Page No.
225
and
http://www.cs.ucsb.edu/~sherwood/cs290/papers/covert-kemmerer.pdf
and
http://www.cs.utexas.edu/~byoung/cs361/lecture16.pdf
and
http://www.cs.utexas.edu/~byoung/cs361/lecture16.pdf

Explanation/Reference:
Explanation:
Class A fires can be extinguished with water. Class A fire extinguishers use water or foam.
Class A fires involve "common combustibles"; these are ordinary combustible materials, such as cloth, wood, paper, and many plastics.
Incorrect Answers:
B: You cannot use water on a Class B fire. A Class B fire is a flammable liquid fire such as gasoline, oil or lacquers. Therefore, this answer is incorrect.
C: You cannot use water on a Class C fire. Class C fires are Electrical fires. Therefore, this answer is incorrect.
D: You cannot use water on a Class D fire. A Class D fire is combustible metals such as magnesium or potassium. Therefore, this answer is incorrect.
References:
Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, 2013, p. 472

Section: Communication and Network Security
Explanation