Defense Against on-Chip Trojans Enabling Traffic Analysis Attacks

Interconnection networks for multi/many-core processors or server systems are the backbone of the system as they enable data communication among the processing cores, caches, memory and other peripherals. Given the criticality of the interconnects, the system can be severely subverted if the interconnection is compromised. The threat of Hardware Trojans (HTs) penetrating complex hardware systems such as multi/many-core processors are increasing due to the increasing presence of third party players in a System-on-chip (SoC) design. Even by deploying naïve HTs, an adversary can exploit the Network-on-Chip (NoC) backbone of the processor and get access to communication patterns in the system. This information, if leaked to an attacker, can reveal important insights regarding the application suites running on the system; thereby compromising the user privacy and paving the way for more severe attacks on the entire system. In this paper, we demonstrate that one or more HTs embedded in the NoC of a multi/many-core processor is capable of leaking sensitive information regarding traffic patterns to an external malicious attacker; who, in turn, can analyze the HT payload data with machine learning techniques to infer the applications running on the processor. Furthermore, to protect against such attacks, we propose a Simulated Annealing-based randomized routing algorithm in the system. The proposed defense is capable of obfuscating the attacker's data processing capabilities to infer the user profiles successfully. Our experimental results demonstrate that the proposed randomized routing algorithm could reduce the accuracy of identifying user profiles by the attacker from >98% to <; 15% in multi/many-core systems.