The First Concept and Real-world Deployment of a GPU-based Thermal Covert Channel: Attack and Countermeasures

Thermal covert channel (TCC) attacks have been studied as a threat to CPU-based systems over recent years. In this paper, we propose a new type of TCC attack that for the first time leverages the Graphics Processing Unit (GPU) of a system to create a stealthy communication channel between two malicious applications. We evaluate our new attack on two different real-world platforms: a GPU-dedicated general computing platform and a GPU-integrated embedded platform. Our results are the first to show that a GPU-based thermal covert channel attack is possible. From our experiments, we obtain a transmission rate of up to 8.75 bps with a very low error rate of less than 2 % for a 12-bit packet size, which is comparable to CPU-based TCCs in the state of the art. Moreover, we show how existing state-of-the-art countermeasures for TCCs need to be extended to tackle the new GPU-based attack at the cost of added overhead. To reduce this overhead, we propose our own DVFS-based countermeasure which mitigates the attack, while causing
$2\times$
less performance loss than the state-of-the-art countermeasure on a set of compute-intensive GPU benchmark applications.