A Covert and Efficient Attack on FPGA Cloud Based on Adaptive RON

The security of the FPGA cloud has become a major concern for both industry and academia due to its widespread use in many vital domains. In this article, we expose a hardware vulnerability in the FPGA cloud and demonstrate a covert and efficient denial-of-service (DoS) attack method that severely threatens the security of the FPGA cloud. First, we adopt a flip-flop-based ring oscillator (RO) to construct an adaptive ring oscillator network (RON). Second, we devise a power and temperature-based resource adjustment algorithm to decide the maximum number of ROs in the adaptive RON. By constraining the size of the adaptive RON, the power and the thermal footprint of the attack process can be reduced. Finally, we design an adaptive frequency sweeping algorithm to automatically search for an effective frequency and perform a successful attack on the FPGA. To validate our method, we conduct exemplary attacks on FPGAs. The results reveal that our method can successfully bypass the design rule checking (DRC) and security measures of the FPGA cloud to crash the FPGA. Besides high-end FPGAs, we demonstrate our method is suitable for some FPGAs with moderate performance. Furthermore, we discuss the impact of the number of ROs and the duty cycle on the proposed method.