Sancus 2.0

Abstract

The Sancus security architecture for networked embedded devices was proposed in 2013 at the USENIX Security conference. It supports remote (even third-party) software installation on devices while maintaining strong security guarantees. More specifically, Sancus can remotely attest to a software provider that a specific software module is running uncompromised and can provide a secure communication channel between software modules and software providers. Software modules can securely maintain local state and can securely interact with other software modules that they choose to trust. Over the past three years, significant experience has been gained with applications of Sancus, and several extensions of the architecture have been investigated—both by the original designers as well as by independent researchers. Informed by these additional research results, this journal version of the Sancus paper describes an improved design and implementation, supporting additional security guarantees (such as confidential deployment) and a more efficient cryptographic core. We describe the design of Sancus 2.0 (without relying on any prior knowledge of Sancus) and develop and evaluate a prototype FPGA implementation. The prototype extends an MSP430 processor with hardware support for the memory access control and cryptographic functionality required to run Sancus. We report on our experience using Sancus in a variety of application scenarios and discuss some important avenues of ongoing and future work.

MicroProfiler: Principled Side-Channel Mitigation through Microarchitectural Profiling

“…However, its implementation is not opensourced, so the precise impact of the DMA side channel we examine cannot be assessed. [2] extends openMSP430 with modified memory access logic and additional instructions to allow hardware-based isolation and attestation of embedded enclaves. While the original Sancus architecture was built on an older version of openMSP430 without DMA support, recent upstream Sancus cores [28] come with additional memory access control logic that allows DMA requests to unprotected memory regions during enclaved execution.…”

“…To demonstrate the applicability of our methodology, we instantiate it for a recently described side-channel attack [23] exploiting subtle timing differences of direct memory access (DMA) requests due to contention in openMSP430 processors [25]. The open-MSP430 core is an open-source implementation of Texas Instruments' popular, low-power MSP430 [22] microcontroller, which has been the basis of several academic security architectures, such as SMART [1], Sancus [2], and the VRASED family of systems [5]- [7]. Notably, several of these security architectures [2], [5]- [7] support untrusted peripherals by explicitly limiting DMA requests to unprotected parts of the memory.…”

“…The open-MSP430 core is an open-source implementation of Texas Instruments' popular, low-power MSP430 [22] microcontroller, which has been the basis of several academic security architectures, such as SMART [1], Sancus [2], and the VRASED family of systems [5]- [7]. Notably, several of these security architectures [2], [5]- [7] support untrusted peripherals by explicitly limiting DMA requests to unprotected parts of the memory. However, it has been recently discovered that such unprivileged DMA requests can trigger contention on the shared memory bus, causing a delay in the request depending on any concurrent memory accesses by the CPU [23].…”

A Survey on Recent Advanced Research of CPS Security

“…In recent years, many types of research have been conducted with Sancus to guarantee the security of IoT devices. Furthermore, Sancus 2.0 [107] with an updated design and implementation was proposed and supports private deployment and more efficient cryptography. The authors developed and evaluated a prototype FPGA implementation to evaluate this scheme in proximal, colocated, and remote settings under surveillance, and the method was proven to defend against acoustic side-channel attacks.…”

Learning Data Structure Shapes from Memory Graphs

“…As an example application, consider trusted execution environments such as Intel SGX [25] or Sancus [28] that provide secure enclaves in which code is executed in isolation from a potentially malicious host system. When data structures with pointers are accessed from within a secure enclave, these pointers may be abused to manipulate the enclave's execution flow.…”