审查制度在野外：分析叙利亚的互联网过滤
Censorship in the Wild: Analyzing Internet Filtering in Syria
摘要：
互联网审查由世界各地的许多政府执行，然而，由于缺乏公开可用的信息，以及执行主动测量的固有风险，研究界通常很难在野外调查审查做法。因此，从部署在叙利亚的7个Blue Coat SG-9000代理服务器中泄漏的600 GB日志，在国家范围内过滤互联网流量，代表了一个独特的机会，可以提供真实世界审查生态系统的详细快照。本文介绍了对泄露的Blue Coat日志进行测量分析的方法和结果，揭示了一种相对隐蔽但相当有针对性的审查。我们发现，流量是通过几种方式过滤的：使用IP地址和域名来阻止广告或网站，以及针对特定内容的关键字或类别。我们发现，基于关键字的审查产生了一些附带损害，因为许多请求被阻止，即使它们不涉及敏感内容。我们还发现，即时通讯受到严格审查，而对社交媒体的过滤仅限于特定页面。最后，我们发现叙利亚用户试图通过使用网络/袜子代理，Tor，VPN和BitTorrent来逃避审查。据我们所知，我们的工作首次对叙利亚的互联网过滤进行了分析。
英文摘要：
Internet censorship is enforced by numerous governments worldwide, however, due to the lack of publicly available information, as well as the inherent risks of performing active measurements, it is often hard for the research community to investigate censorship practices in the wild. Thus, the leak of 600GB worth of logs from 7 Blue Coat SG-9000 proxies, deployed in Syria to filter Internet traffic at a country scale, represents a unique opportunity to provide a detailed snapshot of a real-world censorship ecosystem. This paper presents the methodology and the results of a measurement analysis of the leaked Blue Coat logs, revealing a relatively stealthy, yet quite targeted, censorship. We find that traffic is filtered in several ways: using IP addresses and domain names to block subnets or websites, and keywords or categories to target specific content. We show that keyword-based censorship produces some collateral damage as many requests are blocked even if they do not relate to sensitive content. We also discover that Instant Messaging is heavily censored, while filtering of social media is limited to specific pages. Finally, we show that Syrian users try to evade censorship by using web/socks proxies, Tor, VPNs, and BitTorrent. To the best of our knowledge, our work provides the first analytical look into Internet filtering in Syria.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
