The IP-stride prefetcher has recently been exploited to leak secrets through side-channel attacks. It, however, cannot be simply disabled for security with prefetching speedup as a sacrifice. The state-of-the-art defense tries to retain the prefetching effect by hardware modification. In this paper, we present PhantomFetch as the first prefetching-retentive and hardware-agnostic defense. It avoids potential remanufacturing cost and enriches applicability to off-the-shelf devices. The key idea is to directly break the exploitable coupling between trained prefetcher entries and the victim's secret-dependent loads by obfuscating the sensitive load effects of the victim. The experiment results show that PhantomFetch can secure the IP-stride prefetcher with only negligible overhead.

翻译：IP步幅预取器近期被利用于通过侧信道攻击泄露敏感信息。然而，单纯为安全考虑而禁用该功能将牺牲预取加速效益。现有最先进的防御方案试图通过硬件修改保留预取效果。本文提出PhantomFetch作为首个兼顾预取功能保持与硬件无关性的防御方案。该方法避免了潜在的硬件改造成本，并增强了对现成设备的适用性。其核心思想是通过混淆受害程序中敏感负载的影响，直接打破可被利用的预取器训练条目与受害者秘密相关负载之间的耦合关系。实验结果表明，PhantomFetch能以可忽略的性能开销实现对IP步幅预取器的安全防护。