We present Bastion, a new hardware-software architecture for protecting security-critical software modules in an untrusted software stack. Our architecture is composed of enhanced microprocessor hardware and enhanced hypervisor software. Each trusted software module is provided with a secure, fine-grained memory compartment and its own secure persistent storage area. Bastion is the first architecture to provide direct hardware protection of the hypervisor from both software and physical attacks, before employing the hypervisor to provide the same protection to security-critical OS and application modules. Our implementation demonstrates the feasibility of bypassing an untrusted commodity OS to provide application security and shows better security with higher performance when compared to the Trusted Platform Module (TPM), the current industry state-of-the-art security chip. We provide a proof-of-concept implementation on the OpenSPARC platform.

Remote update of hardware platforms or embedded systems is a convenient service enabled by Field Programmable Gate Array (FPGA)-based systems. This service is often essential in applications like space-based FPGA systems or set-top boxes. However, having the source of the update be remote from the FPGA system opens the door to a set of attacks that may challenge the confidentiality and integrity of the FPGA configuration, the bitstream. Existing schemes propose to encrypt and authenticate the bitstream to thwart these attacks. However, we show that they do not prevent the replay of old bitstream versions, and thus give adversaries an opportunity for downgrading the system. In this article, we propose a new architecture called sarfum that, in addition to ensuring bitstream confidentiality and integrity, precludes the replay of old bitstreams. sarfum also includes a protocol for the system designer to remotely monitor the running configuration of the FPGA. Following our presentation and analysis of the security protocols, we propose an example of implementation with the CCM (Counter with CBC-MAC) authenticated encryption standard. We also evaluate the impact of our architecture on the configuration time for different FPGA devices.