Over the past few years, several research groups have introduced innovative hardware designs for Trusted Execution Environments (TEEs), aiming to secure applications against potentially compromised privileged software, including the kernel. Since 2017, Tang et al. introduced a new class of software-enabled hardware attacks, which leverages energy management mechanisms. These attacks aim at bypassing TEE security guarantees and exposing sensitive information like cryptographic keys. They have increased in prevalence over the past few years. Despite that, current RISC-V TEE architectures have yet to incorporate them into their threat models. Proprietary implementations, such as Arm TrustZone and Intel SGX, embed countermeasures. However, these countermeasures are not viable in the long term and hinder the capabilities of energy management mechanisms. This article presents the first comprehensive knowledge survey of these attacks, along with an evaluation of literature countermeasures. Our analysis highlights a substantial security gap between assumed threat models and the actual ones, presenting considerable threats in modern systems-on-chip that can undermine even the security guarantees provided by TEEs. We advocate for the enhancement of the next generation of RISC-V TEEs to address these attacks within their threat models, and we believe this study will spur further community efforts in this direction.

翻译：过去几年中，多个研究团队为可信执行环境（TEE）引入了创新的硬件设计，旨在保护应用程序免受包括内核在内的潜在特权软件威胁。自2017年起，Tang等人提出了一类新型软件辅助硬件攻击，该类攻击利用能量管理机制，旨在绕过TEE安全保证并泄露加密密钥等敏感信息。近年来此类攻击日益普遍。尽管如此，当前的RISC-V TEE架构尚未将其纳入威胁模型。Arm TrustZone和Intel SGX等专有实现已嵌入防护措施，但这些措施长期来看并不可行，且会限制能量管理机制的功能。本文首次对此类攻击进行了全面知识综述，并对文献中的防护措施进行了评估。我们的分析揭示了假定威胁模型与实际威胁模型之间的重大安全鸿沟，这给现代片上系统带来了巨大风险，甚至可能破坏TEE提供的安全保障。我们主张在下一代RISC-V TEE的威胁模型中增强对此类攻击的防护，并相信本研究将推动学界在此方向展开进一步探索。