Encrypted DNS -> Privacy? A Traffic Analysis Perspective
Encrypted DNS -> Privacy? A Traffic Analysis Perspective
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加密 DNS -> 隐私？
DOI：
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
C. Troncoso
中科院分区：
文献类型：
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作者：
S. Siby;Marc Juárez;Claudia Díaz;Narseo Vallina;C. Troncoso
实际上，每一个与互联网服务的连接都是在没有任何流量级保护的情况下进行DNS查找，从而实现操纵、重定向、监视和审查。为了解决这些问题，Google和Cloudflare等大型组织正在部署最近标准化的协议，这些协议可以加密最终用户和递归解析器（如DNS-over-TLS（DoT）和DNS-over-HTTPS（DoH））之间的DNS流量。在本文中，我们研究加密DNS流量是否可以保护用户免受基于流量分析的监控和审查。我们提出了一个新的功能集来执行攻击，因为那些用于攻击HTTPS或Tor流量不适合DNS的特性。我们表明，流量分析可以在封闭和开放世界设置中高精度地识别域，使用的数据比HTTPS流攻击少124倍。我们发现，位置、解析器、平台或客户端等因素确实会降低攻击性能，但它们远不能完全阻止攻击。我们的研究结果表明，基于DNS的审查仍然是可能的加密DNS流量。事实上，我们证明了标准化的填充方案是无效的。然而，Tor --它不能有效地减轻对Web流量的流量分析攻击--是对DoH流量分析的一个很好的防御。
Virtually every connection to an Internet service is preceded by a DNS lookup which is performed without any traffic-level protection, thus enabling manipulation, redirection, surveillance, and censorship. To address these issues, large organizations such as Google and Cloudflare are deploying recently standardized protocols that encrypt DNS traffic between end users and recursive resolvers such as DNS-over-TLS (DoT) and DNS-over-HTTPS (DoH). In this paper, we examine whether encrypting DNS traffic can protect users from traffic analysis-based monitoring and censoring. We propose a novel feature set to perform the attacks, as those used to attack HTTPS or Tor traffic are not suitable for DNS' characteristics. We show that traffic analysis enables the identification of domains with high accuracy in closed and open world settings, using 124 times less data than attacks on HTTPS flows. We find that factors such as location, resolver, platform, or client do mitigate the attacks performance but they are far from completely stopping them. Our results indicate that DNS-based censorship is still possible on encrypted DNS traffic. In fact, we demonstrate that the standardized padding schemes are not effective. Yet, Tor -- which does not effectively mitigate traffic analysis attacks on web traffic -- is a good defense against DoH traffic analysis.
影响因子：
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作者：
Sheharbano Khattak;T. Elahi;Laurent Simon;C. Swanson;S. Murdoch;I. Goldberg
通讯作者：
Sheharbano Khattak;T. Elahi;Laurent Simon;C. Swanson;S. Murdoch;I. Goldberg