Practical Volume-Based Attacks on Encrypted Databases
Practical Volume-Based Attacks on Encrypted Databases
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DOI：
10.1109/eurosp48549.2020.00030
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发表时间：
2020-08
期刊：
影响因子：
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通讯作者：
Stephanie Wang;Rishabh Poddar;Jianan Lu;Raluca A. Popa
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作者：
Stephanie Wang;Rishabh Poddar;Jianan Lu;Raluca A. Popa
近年来，人们对加密数据库(如不经意的协议)的强安全原语越来越感兴趣，这些原语隐藏了查询执行的访问模式，只显示了结果的数量。然而，最近的工作表明，即使是卷泄漏也可以重建数据库中的整个列。然而，现有的攻击依赖于一组在实践中不现实的假设，例如，它们(I)要求用户发出大量查询，或者(Ii)假设查询或底层数据的某些分布(例如，查询是随机均匀分布的，或者数据库不包含缺失值)。在这项工作中，我们提出了新的攻击来恢复个人用户查询的内容，假设除了结果的数量之外没有从系统泄漏，并避免了上面的限制假设。与以前的攻击不同，我们的攻击只需要用户发出一个查询来恢复关键字。此外，我们的攻击不假设发出的查询或底层数据的分布。相反，我们的主要洞察力是利用现实世界应用程序的行为。我们首先调查11个应用程序，以确定攻击者可以利用的两个关键特征-(L)文件插入和(Ii)自动查询重放。我们提出了利用这两个属性的攻击，并且与任何加密数据库系统的细节无关的卷泄漏。随后，我们通过模拟服务器端对手对真实的Gmail Web客户端执行攻击。我们对Gmail的攻击在几分钟内就完成了，证明了我们技术的可行性。对于采用某些缓解策略的情况，我们还提供了三种辅助攻击。
Recent years have seen an increased interest towards strong security primitives for encrypted databases (such as oblivious protocols) that hide the access patterns of query execution and reveal only the volume of results. However recent work has shown that even volume leakage can enable the reconstruction of entire columns in the database. Yet existing attacks rely on a set of assumptions that are unrealistic in practice for example they (i) require a large number of queries to be issued by the user or (ii) assume certain distributions on the queries or underlying data (e.g. that the queries are distributed uniformly at random or that the database does not contain missing values). In this work we present new attacks for recovering the content of individual user queries assuming no leakage from the system except the number of results and avoiding the limiting assumptions above. Unlike prior attacks our attacks require only a single query to be issued by the user for recovering the keyword. Furthermore our attacks make no assumptions about the distribution of issued queries or the underlying data. Instead our key insight is to exploit the behavior of real-world applications. We start by surveying 11 applications to identify two key characteristics that can be exploited by attackers-(l) file injection and (ii) automatic query replay. We present attacks that leverage these two properties in concert with volume leakage independent of the details of any encrypted database system. Subsequently we perform an attack on the real Gmail web client by simulating a server-side adversary. Our attack on Gmail completes within a matter of minutes demonstrating the feasibility of our techniques. We also present three ancillary attacks for situations when certain mitigation strategies are employed.