LVI: Hijacking Transient Execution through Microarchitectural Load Value Injection

Jo Van Bulck, Daniel Moghimi, Michael Schwarz, Moritz Lipp, Marina Minkin, Daniel Genkin, Yuval Yarom, Berk Sunar, Daniel Gruß, Frank Piessens

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The recent Spectre attack first showed how to inject incorrect branch targets into a victim domain by poisoning microarchitectural branch prediction history. In this paper, we generalize injection-based methodologies to the memory hierarchy by directly injecting  incorrect, attacker-controlled values into a victim’s transient execution. We propose Load Value Injection (LVI) as an innovative technique to reversely exploit Meltdowntype microarchitectural data leakage. LVI abuses that faulting or assisted loads, executed by a legitimate victim program, may transiently use dummy values or poisoned data from various microarchitectural buffers, before eventually being re-issued by the processor. We show how LVI gadgets allow to expose victim secrets and hijack transient control flow. We practically demonstrate LVI in several proof-of-concept attacks against Intel SGX enclaves, and we discuss implications for traditional user process and kernel isolation.
State-of-the-art Meltdown and Spectre defenses, including widespread silicon-level and microcode mitigations, are orthogonal to our novel LVI techniques. LVI drastically widens the spectrum of incorrect transient paths. Fully mitigating our attacks requires serializing the processor pipeline with lfence instructions after possibly every memory load. Additionally and even worse, due to implicit loads, certain instructions have to be blacklisted, including the ubiquitous x86 ret instruction. Intel plans compiler and assembler-based full mitigations that will allow at least SGX enclave programs to remain secure on LVI-vulnerable systems. Depending on the application and optimization strategy, we observe extensive overheads of factor 2 to 19 for prototype implementations of the full mitigation.
Original languageEnglish
Title of host publication2020 IEEE Symposium on Security and Privacy
PublisherInstitute of Electrical and Electronics Engineers
Pages1452-1470
Volume1
ISBN (Electronic)978-1-7281-3497-0
DOIs
Publication statusPublished - 18 May 2020
Event2020 IEEE Symposium on Security and Privacy - Virtuell
Duration: 17 May 202021 May 2020

Conference

Conference2020 IEEE Symposium on Security and Privacy
Abbreviated titleSP 2020
CityVirtuell
Period17/05/2021/05/20

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    Van Bulck, J., Moghimi, D., Schwarz, M., Lipp, M., Minkin, M., Genkin, D., ... Piessens, F. (2020). LVI: Hijacking Transient Execution through Microarchitectural Load Value Injection. In 2020 IEEE Symposium on Security and Privacy (Vol. 1, pp. 1452-1470). Institute of Electrical and Electronics Engineers. https://doi.org/10.1109/SP40000.2020.00089