The Gates of Time: Improving Cache Attacks with Transient Execution

Daniel Katzman, William Kosasih, Chitchanok Chuengsatiansup, Eyal Ronen, Yuval Yarom

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


For over two decades, cache attacks have been shown to pose a significant risk to the security of computer systems. In particular, a large number of works show that cache attacks provide a stepping stone for implementing transient-execution attacks. However, much less effort has been expended investigating the reverse direction—how transient execution can be exploited for cache attacks. In this work, we answer this question. We first show that using transient execution, we can perform arbitrary manipulations of the cache state. Specifically, we design versatile logical gates whose inputs and outputs are the caching state of memory addresses. Our gates are generic enough that we can implement them in WebAssembly. Moreover, the gates work on processors from multiple vendors, including Intel, AMD, Apple, and Samsung. We demonstrate that these gates are Turing complete and allow arbitrary computation on cache states, without exposing the logical values to the architectural state of the program. We then show two use cases for our gates in cache attacks. The first use case is to amplify the cache state, allowing us to create timing differences of over 100 millisecond between the cases that a specific memory address is cached or not. We show how we can use this capability to build eviction sets in WebAssembly, using only a low-resolution (0.1 millisecond) timer. For the second use case, we present the Prime+Store attack, a variant of Prime+Probe that decouples the sampling of cache states from the measurement of said state. Prime+ Store is the first timing-based cache attack that can sample the cache state at a rate higher than the clock rate. We show how to use Prime+Store to obtain bits from a concurrently executing modular exponentiation, when the only timing signal is at a resolution of 0.1 millisecond.

Original languageEnglish
Title of host publication32nd USENIX Security Symposium, USENIX Security 2023
PublisherUSENIX Association
Number of pages18
ISBN (Electronic)9781713879497
StatePublished - 2023
Event32nd USENIX Security Symposium, USENIX Security 2023 - Anaheim, United States
Duration: 9 Aug 202311 Aug 2023

Publication series

Name32nd USENIX Security Symposium, USENIX Security 2023


Conference32nd USENIX Security Symposium, USENIX Security 2023
Country/TerritoryUnited States


FundersFunder number
Intel Corporation
Association pour la Recherche sur le CancerDE200101577, DP210102670
Commonwealth Scientific and Industrial Research Organisation
University of Adelaide
Tel Aviv University


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