Which of the following can be used as a covert channel?

A.
Storage and timing.

B.
Storage and low bits.

C.
Storage and permissions.

D.
Storage and classification.

Explanation:
Those are the proper elements, you can use these two to achieve a covert channel.
Low bits is not a term related to covert channels. Permissions are related to authentication, they
do not achieve what the question wants. Also, classification is could not selected as a correct
choice.
Check your official CISSP documentation to see what can be used as a covert channel.
“An active variation on eavesdropping is called Covert Channel eavesdropping, which consists of
using a hidden unauthorized network connection to communicate unauthorized information. A
Covert Storage Channel operates by writing information to storage by one process and then

reading by using another process from a different security level. A Covert Timing Channel signals
information to another process by modulating its own resource use to affect the response time of
another.” Pg. 101 Krutz: The CISSP Prep Guide: Gold Edition