一句话:揭示乱序执行本身可被滥用来构造隐蔽细粒度计时器,使侧信道攻击面比瞬态执行漏洞更广。
侧信道攻击对许多安全模型构成严重威胁,尤其是基于沙箱的浏览器。以往,人们通常把 Spectre、Meltdown 等漏洞归咎于乱序处理器中的瞬态执行侧信道。本文提出 Hacky Racers,转而利用指令级并行性来生成隐蔽的细粒度计时器,并证明乱序执行本身造成安全破坏的能力远比瞬态执行更普遍。通过这一方式,作者展示了乱序执行可支持新型侧信道计时,从而扩大攻击面。摘要未展开具体实现与实验评估,但核心贡献在于揭示并利用乱序执行中指令级并行这一常被忽视的侧信道来源,对处理器安全和浏览器沙箱模型具有重要影响。
Side-channel attacks pose serious threats to many security models, especially sandbox-based browsers. While transient-execution side channels in out-of-order processors have previously been blamed for vulnerabilities such as Spectre and Meltdown, we show that in fact, the capability of out-of-order execution itself to cause mayhem is far more general.