Bulck, J.
Oswald, D.
Marin, E.
Aldoseri, A.
Garcia, F.
Piessens, F.
2020-08-10
<p>This paper analyzes the vulnerability space arising in Trusted Execution Environments (TEEs) when interfacing a trusted enclave application with untrusted, potentially malicious code. Considerable research and industry effort has gone into developing TEE runtime libraries with the purpose of transparently shielding enclave application code from an adversarial environment. However, our analysis reveals that shielding requirements are generally not well-understood in real-world TEE runtime implementations. We expose several sanitization vulnerabilities at the level of the Application Binary Interface (ABI) and the Application Programming Interface (API) that can lead to exploitable memory safety and sidechannel vulnerabilities in the compiled enclave. Mitigation of these vulnerabilities is not as simple as ensuring that pointers are outside enclave memory. In fact, we demonstrate that state-of-the-art mitigation techniques such as Intel’s edger8r, Microsoft’s “deep copy marshalling”, or even memory-safe languages like Rust fail to fully eliminate this attack surface. Our analysis reveals 35 enclave interface sanitization vulnerabilities in 8 major open-source shielding frameworks for Intel SGX, RISC-V, and Sancus TEEs. We practically exploit these vulnerabilities in several attack scenarios to leak secret keys from the enclave or enable remote code reuse. We have responsibly disclosed our findings, leading to 5 designated CVE records and numerous security patches in the vulnerable open-source projects, including the Intel SGX-SDK, Microsoft Open Enclave, Google Asylo, and the Rust compiler.</p>
https://doi.org/10.5281/zenodo.3978120
oai:zenodo.org:3978120
eng
Zenodo
https://zenodo.org/communities/futuretpm-h2020
https://zenodo.org/communities/eu
https://doi.org/10.5281/zenodo.3978119
info:eu-repo/semantics/openAccess
Creative Commons Attribution 4.0 International
https://creativecommons.org/licenses/by/4.0/legalcode
ACM CCS 2019, 26th ACM Conference on Computer and Communications Security, London, UK, November 11-15, 2019
Trusted execution
TEE
Intel SGX
memory safety
side-channels
A Tale of TwoWorlds: Assessing the Vulnerability of Enclave Shielding Runtimes
info:eu-repo/semantics/conferencePaper