[论文解读] V0LTpwn: Attacking x86 Processor Integrity from Software

Zijo Kenjar, Tommaso Frassetto+3 more|TUbilio (Technical University of Darmstadt)|Dec 10, 2019

Security and Verification in Computing参考文献 39被引用 35

一句话总结

一种软件控制的 undervolting 攻击，降低 x86 处理器的完整性，使不会导致崩溃的错误执行成为可能，并影响跨多个 CPU 版本的 Intel SGX 等 enclave 的计算。

ABSTRACT

Fault-injection attacks have been proven in the past to be a reliable way of bypassing hardware-based security measures, such as cryptographic hashes, privilege and access permission enforcement, and trusted execution environments. However, traditional fault-injection attacks require physical presence, and hence, were often considered out of scope in many real-world adversary settings. In this paper we show this assumption may no longer be justified. We present V0LTpwn, a novel hardware-oriented but software-controlled attack that affects the integrity of computation in virtually any execution mode on modern x86 processors. To the best of our knowledge, this represents the first attack on x86 integrity from software. The key idea behind our attack is to undervolt a physical core to force non-recoverable hardware faults. Under a V0LTpwn attack, CPU instructions will continue to execute with erroneous results and without crashes, allowing for exploitation. In contrast to recently presented side-channel attacks that leverage vulnerable speculative execution, V0LTpwn is not limited to information disclosure, but allows adversaries to affect execution, and hence, effectively breaks the integrity goals of modern x86 platforms. In our detailed evaluation we successfully launch software-based attacks against Intel SGX enclaves from a privileged process to demonstrate that a V0LTpwn attack can successfully change the results of computations within enclave execution across multiple CPU revisions.

研究动机与目标

• 证明软件能够对物理 CPU 核心进行 undervolt，以诱发不可恢复的硬件故障。
• 显示此类故障可在不导致崩溃的情况下损坏执行结果，从而实现完整性入侵。
• 展示对现代 x86 平台的影响，包括特权进程影响 SGX enclaves 的情况。

提出的方法

• 提出并实现一种软件控制的 undervolting 技术，以诱发硬件故障。
• 在多种执行模式下分析由此产生的计算完整性。
• 在特权访问下评估该攻击对 Intel SGX enclaves 的影响。
• 将该攻击的能力与以投机执行为重点的先前侧信道攻击进行比较。

实验结果

研究问题

• RQ1 软件控制的 undervolting 是否会在 x86 CPU 上引发不可恢复的硬件故障，从而破坏计算结果？
• RQ2 V0LTpwn 是否在不同执行模式和 CPU 版本下影响完整性？
• RQ3 在不导致崩溃的情况下诱导错误的 enclave 计算（例如 Intel SGX）是否可行？
• RQ4 这一面向硬件的攻击与现有的侧信道/向量攻击有何不同与互补？

主要发现

• 基于软件的 undervolting 可以产生不可恢复的硬件故障，从而在不崩溃的情况下损坏计算结果。
• 当由特权进程执行时，该攻击可破坏 Intel SGX enclaves 内的计算。
• V0LTpwn 展示了跨多个 CPU 版本的完整性入侵，表明广泛适用性。
• 该方法与以往以投机执行为核心的侧信道攻击形成对比，它针对计算完整性，而不仅仅是信息泄露。