Description
Caches leak information through timing measurements and so-called side-channel attacks. Several primitives exist with different requirements and trade-offs. Flush+Flush is a stealthy and fast cache attack primitive that uses the timing of the clflush instruction depending on the presence of a line in the cache. However, the CPU interconnect plays a bigger role than thought in these timings, and therefore in the error rate of Flush+Flush.
In this paper, we show that a naive implementation that does not take into account the topology of the interconnect yields very important error rates, especially on modern CPUs as the number of cores increases. We, therefore, reverse-engineer this topology and revisit the calibration phase of Flush+Flush for different attacker models to determine the correct threshold for clflush hits and misses. We evaluate that our method yields noiseless side-channel attacks by attacking the AES T-tables implementation of OpenSSL, and by building a covert channel. We obtain a maximal capacity of 3.15 Mbit/s with our improved method, compared to 1.4 Mbit/s with a naive implementation of Flush+Flush on an Intel Core i9-9900 CPU.
Next sessions
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Fine-grained dynamic partitioning against cache-based side channel attacks
Speaker : Nicolas Gaudin - Trasna
The growth of embedded systems takes advantage of architectural advances from modern processors to increase performance while maintaining a low power consumption. Among these advances is the introduction of cache memory into embedded systems. These memories speed up the memory accesses by temporarily storing data close to the execution core. Furthermore, data from different applications share the[…]-
SemSecuElec
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Micro-architectural vulnerabilities
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Hardware architecture
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Side-Channel Based Disassembly on Complex Processors: From Microachitectural Characterization to Probabilistic Models
Speaker : Julien Maillard - CEA
Side-Channel Based Disassembly (SCBD) is a category of Side-Channel Analysis (SCA) that aims at recovering information on the code executed by a processor through the observation of physical side-channels such as power consumption or electromagnetic radiations. While traditional SCA often targets cryptographic keys, SCBD focuses on retrieving assembly code that can hardly be extracted via other[…]-
SemSecuElec
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Side-channel
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Hardware reverse
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PhaseSCA: Exploiting Phase-Modulated Emanations in Side Channels
Speaker : Pierre Ayoub - LAAS-CNRS
In recent years, the limits of electromagnetic side-channel attacks have been significantly expanded.However, while there is a growing literature on increasing attack distance or performance, the discovery of new phenomenons about compromising electromagnetic emanations remains limited. In this work, we identify a novel form of modulation produced by unintentional electromagnetic emanations: phase[…]-
Side-channel
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Conformité TEMPEST et compromission d’information au travers de l’arbre d’alimentation d’un équipement
Speaker : Tristan PECHERAU, David HARDY - Thalès
THALES conçoit des équipements cryptographiques et de radiocommunication tactiques, navales et aéronautiques, embarquant des éléments de chiffrement pour la sécurité des communications. Cette sécurité notamment d’un point de vue des émanations électromagnétiques est normée. Ces normes de sécurité de l’information, sont connues sous le nom de code “TEMPEST”, correspondant aux normes OTAN SDIP-27,[…] -
Prise de contrôle d’un infodivertissement automobile à distance
Speaker : Philippe Trebuchet, Guillaume Bouffard - ANSSI
Les véhicules connectés intègrent de nombreuses technologies de communications sans-fil à distance, comme celles exploitant les protocoles Bluetooth ou WiFi. Si le gain en confort d’utilisation et d’interaction est notable, la mise à disposition de ce type d’interfaces augmente les risques en matière de cybersécurité. Dans cet article, nous analysons l’implémentation de la pile Bluetooth embarquée[…]-
SemSecuElec
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Network
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Embedded systems
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