论文标题
对加密数据库的实际量攻击
Practical Volume-Based Attacks on Encrypted Databases
论文作者
论文摘要
近年来,人们对加密数据库的强大安全性原始图(例如遗忘协议)的兴趣增加,这些数据库隐藏了查询执行的访问模式,并仅揭示结果的量。但是,最近的工作表明,即使音量泄漏也可以使数据库中的整列重建。但是,现有的攻击依赖于实践中不现实的一组假设:例如,他们(i)需要用户发出大量查询,或者(ii)在查询或基础数据上假设某些分布(例如,查询是随机分布的,或数据库不含缺失值,则这些查询是均匀分布的)。 在这项工作中,我们提出了用于恢复单个用户查询内容的新攻击,假设除了结果数,并且避免了上述限制假设,则没有从系统中泄漏。与先前的攻击不同,我们的攻击仅需要用户发出单个查询以恢复关键字。此外,我们的攻击对发行的查询或基础数据的分布没有任何假设。相反,我们的主要见解是利用现实世界应用程序的行为。 首先,我们调查11个应用程序,以确定攻击者可以利用的两个关键特征:(i)文件注入,以及(ii)自动查询重播。我们提出了与音量泄漏共同利用这两个属性的攻击,与任何加密数据库系统的详细信息无关。随后,我们通过模拟服务器端对手对真实的Gmail Web客户端进行攻击。我们对Gmail的攻击在几分钟之内完成,证明了我们的技术的可行性。当采用某些缓解策略时,我们还为情况提出了三项辅助攻击。
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: (i) 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.