一句话：提出 Debreach，用污点分析与程序变换消除压缩输出长度对敏感数据的依赖，兼顾泄漏防护与压缩率。
压缩侧信道是 Web 应用中一类可利用的信息泄漏源，而现有缓解手段要么严重降低压缩率，要么需要开发者付出过多适配成本。Debreach 采用静态分析与程序变换相结合的方法：首先通过污点分析可靠地识别程序中的敏感数据流，并用代码插桩在数据进入压缩器前进行标注；随后增强压缩器，利用标准压缩协议允许“不压缩”的自由度，从而切断敏感数据与压缩输出大小之间的依赖关系。由于 Debreach 自动插桩应用且不修改压缩协议，因此对现有系统非侵入且兼容。作者在一组 PHP Web 服务器应用上评估了该方法，实验表明其在保证无泄漏的同时，相比当前最优方法能取得显著更高的压缩性能。
Compression is an emerging source of exploitable side-channel leakage that threatens data security, particularly in web applications where compression is indispensable for performance reasons. Current approaches to mitigating compression side channels have drawbacks in that they either degrade compression ratio drastically or require too much effort from developers to be widely adopted. To bridge the gap, we develop Debreach, a static analysis and program transformation based approach to mitigating compression side channels. Debreach consists of two steps. First, it uses taint analysis to soundly identify flows of sensitive data in the program and uses code instrumentation to annotate data before feeding them to the compressor. Second, it enhances the compressor to exploit the freedom to not compress of standard compression protocols, thus removing the dependency between sensitive data and the size of the compressor's output. Since Debreach automatically instruments applications and does not change the compression protocols, it has the advantage of being non-disruptive and compatible with existing systems. We have evaluated Debreach on a set of web server applications written in PHP. Our experiments show that, while ensuring leakage-freedom, Debreach can achieve significantly higher compression performance than state-of-the-art approaches.
DOI 原文 ·
@inproceedings{paperbot5230,
title = {Debreach: Mitigating Compression Side Channels via Static Analysis and Transformation},
author = {Brandon Paulsen and Chungha Sung and Peter A.H. Peterson and Chao Wang},
booktitle = {ASE},
year = {2019},
doi = {10.1109/ase.2019.00088}
}