What would BEST define a covert channel?
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A. B. C. D.The Answer: A communication channel that allows transfer of information in a manner that violates the system's security policy.
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 systems security policy.
The channel to transfer this unauthorized data is the result of one of the following conditions: Oversight in the development of the productImproper implementation of access controlsExistence of a shared resource between the two entitiesInstallation of a Trojan horse The following answers are incorrect: An undocumented backdoor that has been left by a programmer in an operating system is incorrect because it is not a means by which unauthorized transfer of information takes place.Such backdoor is usually referred to as a Maintenance Hook.
An open system port that should be closed is incorrect as it does not define a covert channel.
A trojan horse is incorrect because it is a program that looks like a useful program but when you install it it would include a bonus such as a Worm, Backdoor, or some other malware without the installer knowing about it.
Reference(s) used for this question: Shon Harris AIO v3 , Chapter-5 : Security Models & Architecture AIOv4 Security Architecture and Design (pages 343 - 344) AIOv5 Security Architecture and Design (pages 345 - 346)
A covert channel is a communication mechanism that is used to transfer information in a manner that violates the security policy of the system. It is usually used to bypass security mechanisms that are in place to prevent unauthorized access or transfer of information.
Option A, "An undocumented backdoor that has been left by a programmer in an operating system," is not an accurate definition of a covert channel. While an undocumented backdoor may allow unauthorized access to a system, it is not necessarily a covert channel, which involves the transfer of information.
Option B, "An open system port that should be closed," is also not an accurate definition of a covert channel. An open system port may be a vulnerability that could be exploited by attackers, but it is not necessarily a covert channel, which involves the intentional transfer of information.
Option D, "A trojan horse," is also not an accurate definition of a covert channel. A trojan horse is a type of malware that disguises itself as legitimate software to gain unauthorized access to a system or steal information. While a trojan horse may be used to create a covert channel, it is not the same thing as a covert channel.
Therefore, the correct answer is C, "A communication channel that allows transfer of information in a manner that violates the system's security policy." A covert channel can take many forms, such as a hidden file or a secret communication channel between two processes. The key characteristic of a covert channel is that it violates the security policy of the system by allowing the unauthorized transfer of information.