How do covert timing channels convey information?

A.
By generating noise and traffic with the data

B.
By modifying the timing of a system resource in some measurable way

C.
By changing a system’s stored data characteristics

D.
By performing a covert channel analysis

Explanation:
The correct answer is “By modifying the timing of a system resource in some measurable way”. A
covert timing channel alters the timing of parts of the system to enable it to be used to
communicate information covertly (outside the normal security function).
* Answer “By changing a system’s stored data characteristics” is the description of the use of a
covert storage channel.
* “By generating noise and traffic with the data” is a technique to combat the use of covert
channels.
* Answer “By performing a covert channel analysis” is the Orange Book requirement for B3, B2,
and A1 evaluated systems.