一句话：提出安全硬件架构 Morpheus，通过移动目标防御集合与 churn 持续混淆程序值，抵御控制流攻击。
攻击常利用程序语义与机器语义之间的鸿沟，例如定位敏感指针、覆盖敏感数据并劫持执行。Morpheus 将这些攻击者需要而正常程序不用的信息持续混淆，包括代码与指针的表示以及代码和数据的精确位置。该安全硬件架构结合移动目标防御集合与churn：前者随机化关键程序值（重定位指针、加密代码和指针），后者在系统运行中透明地重新随机化。基于 RISC-V 的原型用于阻止控制流攻击。每个防御借助硬件支持以更低开销提供更多随机性；与churn组合后可高覆盖防御多种控制流攻击，包括高级攻击和设计后披露的攻击；churn周期达50 ms时性能影响仅约1%，估计比可能攻破系统所需时间快至少5000倍。
Attacks often succeed by abusing the gap between program and machine-level semantics-- for example, by locating a sensitive pointer, exploiting a bug to overwrite this sensitive data, and hijacking the victim program's execution. In this work, we take secure system design on the offensive by continuously obfuscating information that attackers need but normal programs do not use, such as representation of code and pointers or the exact location of code and data. Our secure hardware architecture, Morpheus, combines two powerful protections: ensembles of moving target defenses and churn. Ensembles of moving target defenses randomize key program values (e.g., relocating pointers and encrypting code and pointers) which forces attackers to extensively probe the system prior to an attack. To ensure attack probes fail, the architecture incorporates churn to transparently re-randomize program values underneath the running system. With frequent churn, systems quickly become impractically difficult to penetrate. We demonstrate Morpheus through a RISC-V-based prototype designed to stop control-flow attacks. Each moving target defense in Morpheus uses hardware support to individually offer more randomness at a lower cost than previous techniques. When ensembled with churn, Morpheus defenses offer strong protection against control-flow attacks, with our security testing and performance studies revealing: i) high-coverage protection for a broad array of control-flow attacks, including protections for advanced attacks and an attack disclosed after the design of Morpheus, and ii) negligible performance impacts (1%) with churn periods up to 50 ms, which our study estimates to be at least 5000x faster than the time necessary to possibly penetrate Morpheus.
@inproceedings{paperbot4890,
title = {Morpheus},
author = {Mark Gallagher and Lauren Biernacki and Shibo Chen and Zelalem Birhanu Aweke and Salessawi Ferede Yitbarek and Misiker Tadesse Aga and Austin Harris and Zhixing Xu and Baris Kasikci and Valeria Bertacco and Sharad Malik and Mohit Tiwari and Todd Austin},
booktitle = {ASPLOS},
year = {2019},
doi = {10.1145/3297858.3304037}
}