Powerhammering through Glitch Amplification – Attacks and Mitigation

Recent work on FPGA hardware security showed a substantial potential risk through power-hammering, which uses high switching activity in order to create excessive dynamic power loads. Virtually all present power-hammering attack scenarios are based on some kind of ring oscillators for which mitigation strategies exist. In this paper, we use a different strategy to create excessive dynamic power consumption: glitch amplification. By carefully designing XOR trees, fast switching wires can be implemented that, while driving high fan-out nets, can draw enough power to crash an FPGA. In addition to the attack (which is crashing an Ultra96 board), we will present a scanner for detecting malicious glitch amplifying FPGA designs.