Covert Channels In Systems Research Articles

Mitigating covert channels based on analysis of the potential for communication

The existence and usage of covert channels in systems of communicating agents poses a significant threat to the confidentiality of information. It is difficult to fully prevent the possibility of covert channels in a system without limiting the communication between its components or negatively affecting its behaviour. However, by developing an understanding of when a covert channel may exist in a given system and which agents are more prone to covert channels than others, approaches for mitigating covert channels can be developed in such a way that they are able to preserve overall system functionality and the communication between its components and with its environment. In this paper, we propose an approach for mitigating covert channels in systems of communicating agents based on an analysis of the potential for communication amongst system agents. First, we propose a mathematical framework for communication and concurrency called Communicating Concurrent Kleene Algebra (C2KA). We use C2KA to present a formulation of the potential for communication condition for covert channel existence. Then, we show how to use the proposed formulation and its mathematical background to analyse systems of communicating agents in order to devise an approach for modifying the behaviours of agents in a system of communicating agents in order to eliminate the potential for communication, thus eliminating the potential for a covert channel, while still preserving the overall system functionality. Using an illustrative example, we show how to specify a system of communicating agents using the mathematical framework of C2KA and we demonstrate and discuss the proposed mitigation approach. We also report on the use of a prototype tool that supports the automated verification and analysis of the potential for communication condition for covert channel existence.

On the Necessary Conditions for Covert Channel Existence: A State-of-the-Art Survey

With the ability to leak confidential information in a secret manner, covert channels pose a significant threat to the confidentiality of a system. Due to this threat, the identification of covert channel existence has become an important part of the evaluation of secure systems. In this paper, we present a state-of-the-art survey discussing the conditions for covert channel existence found in the literature and we point to their inadequacy. We also examine how conditions for covert channel existence are handled by information theory. We propose a set of necessary and verifiable conditions for covert channel existence in systems of communicating agents. We aim to provide an improved understanding of covert channel communication and to build a foundation for developing effective and efficient mechanisms for mitigating covert channels in systems of communicating agents at the early stages of software development