Your Censor is My Censor: Weaponizing Censorship Infrastructure for Availability Attacks
Your Censor is My Censor: Weaponizing Censorship Infrastructure for Availability Attacks
复制标题
DOI：
10.1109/spw53761.2021.00059
复制
发表时间：
2021-05
期刊：
影响因子：
--
通讯作者：
Kevin Bock;Pranav Bharadwaj;Jasraj Singh;Dave Levin
中科院分区：
文献类型：
--
作者：
Kevin Bock;Pranav Bharadwaj;Jasraj Singh;Dave Levin
全国性的互联网审查威胁到生活在审查制度下的数百万用户自由和开放地获得通信和信息。在本文中，我们表明，这对互联网构成了比以前所理解的更大的威胁。我们展示了一个偏离路径的攻击，利用了一个很少研究，但广泛的功能，许多审查基础设施：残留审查，其中审查员继续阻止两个终端主机之间的流量一段时间后，审查事件。我们的攻击发送带有审查内容的欺骗数据包，使两个受害者终端主机被审查器分开，无法相互通信。虽然概念上很简单，但这种攻击有几个挑战，我们解决。我们通过两项研究证明了攻击的可行性：一项是捕获剩余审查的当前状态，另一项是实际发起攻击（针对我们控制的机器）。我们表明，攻击可以发起，尽管有状态的TCP跟踪使用许多审查，它也对那些审查空路由。我们将公开我们的代码。
Nationwide Internet censorship threatens free and open access to communication and information for millions of users living inside of censoring regimes. In this paper, we show that this poses an even greater threat to the Internet than previously understood. We demonstrate an off-path attack that exploits a little-studied but widespread feature of many censoring infrastructures: residual censorship, in which a censor continues blocking traffic between two end-hosts for some time after a censorship event. Our attack sends spoofed packets with censored content, keeping two victim end-hosts separated by a censor from being able to communicate with one another. Although conceptually simple, this attack has several challenges, which we address. We demonstrate the feasibility of the attack through two studies: one to capture the current state of residual censorship, and another to actually launch the attack (against machines we control). We show that the attack can be launched despite stateful TCP tracking used by many censors, and that it also works against those who censor by null-routing. We will be making our code publicly available.