MicroScope: Enabling microarchitectural replay attacks

Dimitrios Skarlatos, Mengjia Yan, Bhargava Gopireddy, Read Sprabery, Josep Torrellas, Christopher W. Fletcher

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


The popularity of hardware-based Trusted Execution Environments (TEEs) has recently skyrocketed with the introduction of Intel's Software Guard Extensions (SGX). In SGX, the user process is protected from supervisor software, such as the operating system, through an isolated execution environment called an enclave. Despite the isolation guarantees provided by TEEs, numerous microarchitectural side channel attacks have been demonstrated that bypass their defense mechanisms. But, not all hope is lost for defenders: many modern fine-grain, high-resolution side channels - -e.g., execution unit port contention - -introduce large amounts of noise, complicating the adversary's task to reliably extract secrets. In this work, we introduce Microarchitectural Replay Attacks, whereby an SGX adversary can denoise nearly arbitrary microarchitectural side channels in a single run of the victim, by causing the victim to repeatedly replay on a page faulting instruction. We design, implement, and demonstrate our ideas in a framework, called MicroScope, and use it to denoise notoriously noisy side channels. Our main result shows how MicroScope can denoise the execution unit port contention channel. Specifically, we show how Micro-Scope can reliably detect the presence or absence of as few as two divide instructions in a single logical run of the victim program. Such an attack could be used to detect subnormal input to individual floating-point instructions, or infer branch directions in an enclave despite today's countermeasures that flush the branch predictor at the enclave boundary. We also use MicroScope to single-step and denoise a cache-based attack on the OpenSSL implementation of AES. Finally, we discuss the broader implications of microarchitectural replay attacks - -as well as discuss other mechanisms that can cause replays.

Original languageEnglish (US)
Title of host publicationISCA 2019 - Proceedings of the 2019 46th International Symposium on Computer Architecture
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages14
ISBN (Electronic)9781450366694
StatePublished - Jun 22 2019
Event46th International Symposium on Computer Architecture, ISCA 2019 - Phoenix, United States
Duration: Jun 22 2019Jun 26 2019

Publication series

NameProceedings - International Symposium on Computer Architecture
ISSN (Print)1063-6897


Conference46th International Symposium on Computer Architecture, ISCA 2019
Country/TerritoryUnited States


  • Operating system
  • Security
  • Side-channel
  • Virtual memory

ASJC Scopus subject areas

  • Hardware and Architecture


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