This paper studies and evaluates the extent to which automated compiler techniques can defend against timing-based side-channel attacks on modern x86 processors. We study how modern x86 processors can leak timing information through sidechannels that relate to control flow and data flow. To eliminate key-dependent control flow and key-dependent timing behavior related to control flow, we propose the use of if-conversion in a compiler backend, and evaluate a proof-of-concept prototype implementation. Furthermore, we demonstrate two ways in which programs that lack key-dependent control flow and keydependent cache behavior can still leak timing information on modern x86 implementations such as the Intel Core 2 Duo, and propose defense mechanisms against them.

Abstract-In this paper, we present Disjoint Code Layouts (DCL), a technique that complements Multi-Variant Execution [1] and W⊕X protection to effectively immunize programs against control flow hijacking exploits such as Return Oriented Programming (ROP) [2] and return-to-libc attacks [3]. DCL improves upon Address Space Partitioning (ASP), an earlier technique presented to defeat memory exploits. Unlike ASP, our solution keeps the full virtual address space available to the protected program. Additionally, our combination of DCL with Multi-Variant Execution is transparent to both the user and the programmer and incurs much less overhead than other ROP defense tools, both in terms of run time and memory footprint.

This paper studies and evaluates the extent to which automated compiler techniques can defend against timing-based side channel attacks on modern x86 processors. We study how modern x86 processors can leak timing information through side channels that relate to data flow. We study the efficiency, effectiveness, portability, predictability and sensitivity of several mitigating code transformations that eliminate or minimize key-dependent execution time variations. Furthermore, we discuss the extent to which compiler backends are a suitable tool to provide automated support for the proposed mitigations.

Code protections aim at blocking (or at least delaying) reverse engineering and tampering attacks to critical assets within programs. Knowing the way hackers understand protected code and perform attacks is important to achieve a stronger protection of the software assets, based on realistic assumptions about the hackers' behaviour. However, building such knowledge is difficult because hackers can hardly be involved in controlled experiments and empirical studies.The FP7 European project Aspire has given the authors of this paper the unique opportunity to have access to the professional penetration testers employed by the three industrial partners. In particular, we have been able to perform a qualitative analysis of three reports of professional penetration test performed on protected industrial code.Our qualitative analysis of the reports consists of open coding, carried out by 7 annotators and resulting in 459 annotations, followed by concept extraction and model inference. We identified the main activities: understanding, building attack, choosing and customizing tools, and working around or defeating protections. We built a model of how such activities take place. We used such models to identify a set of research directions for the creation of stronger code protections.2 https://aspire-fp7.eu

When critical assets or functionalities are included in a piece of software accessible to the end users, code protections are used to hinder or delay the extraction or manipulation of such critical assets. The process and strategy followed by hackers to understand and tamper with protected software might differ from program understanding for benign purposes. Knowledge of the actual hacker behaviours while performing real attack tasks can inform better ways to protect the software and can provide more realistic assumptions to the developers, evaluators, and users of software protections.