Reading Between the Dies: Cross-SLR Covert Channels on Multi-Tenant Cloud FPGAs

Ilias Giechaskiel, Kasper Rasmussen, Jakub Szefer
2019 2019 IEEE 37th International Conference on Computer Design (ICCD)  
Field-Programmable Gate Arrays (FPGAs) are becoming increasingly available via commercial cloud providers, which currently allocate devices on a per-user basis. As the underlying hardware is often underutilized, several proposals for multi-tenant use of FPGA resources have been brought forth, along with some initial work on security attacks in this setting. Simultaneously, high-end FPGAs are being produced with 2.5D integration of multiple distinct dies, called Super Logic Regions (SLRs), onto
more » ... he same chip. Although one might expect that physical separation of logic onto separate dies could prevent multitenant attacks, this paper demonstrates for the first time that cross-SLR information leaks based on sensing voltage changes within the FPGA chip are possible, without physical access to or modification of the boards. The cross-SLR covert channel is characterized analytically and experimentally on five Xilinx Virtex UltraScale+ FPGAs, both locally and on the Amazon and Huawei clouds. Several configurations of the source transmitters and the sink receivers are tested, including their locations, types, and sizes. The power-based channel is shown to have a bandwidth upwards of 4.6 Mbps and accuracy of over 97.6%. Consequently, as physical separation of tenants onto separate dies (SLRs) is an insufficient countermeasure against information leaks, hardware-level architectural improvements are necessary to make secure multi-tenant FPGAs on shared clouds a reality.
doi:10.1109/iccd46524.2019.00010 dblp:conf/iccd/GiechaskielRS19 fatcat:iwhajmm6vvhlxjkrpygb3dynnu