FPGADefender: Malicious Self-Oscillator Scanning for Xilinx UltraScale+ FPGAs

Sharing configuration bitstreams rather than netlists is a very desirable feature to protect IP or to share IP without longer CAD tool processing times. Furthermore, an increasing number of systems could hugely benefit from serving multiple users on the same FPGA, for example, for resource pooling in cloud infrastructures.
This paper researches the threat that a malicious application can impose on an FPGA based system in a multi-tenancy scenario from a hardware security point of view. In particular, this paper evaluates the risk systematically for FPGA power-hammering through short-circuits and self-oscillating circuits which potentially may cause harm to a system. This risk includes implementing, tuning, and evaluating all FPGA self-oscillators known from the literature, but also, developing a large number of new power-hammering designs which have not been considered before. Our experiments demonstrate that malicious circuits can be tuned to the point that just 3% of the logic available on an Ultra96 FPGA board can draw the power budget of the entire FPGA board. This fact suggests a waste power potential for datacenter FPGAs in the range of kilowatts.
In addition to carefully analyzing FPGA hardware security threats, we present the FPGA virus scanner FPGADefender that can detect (possibly) any self-oscillating FPGA circuit, as well as detecting short-circuits, high fanout nets, and a tapping onto signals outside the scope of a module for protecting data center FPGAs such as Xilinx UltraScale+ devices at the bitstream level.