免费代理揭秘：免费代理服务的漏洞与纵向分析
Free Proxies Unmasked: A Vulnerability and Longitudinal Analysis of Free Proxy Services
AI总结：
本文对来自11家提供商的640,600余个免费Web代理开展30个月纵向测量，揭示其低稳定性、大量可利用漏洞及内容篡改风险。
摘要：
自Web早期以来，免费代理便广泛存在，帮助用户绕过受地理封锁的内容并隐藏其IP地址。各类代理提供商承诺更快的互联网或更强的隐私，同时宣传其由数百个随时可用的免费代理组成的列表。然而，付费代理服务会宣传对加密连接和高稳定性的支持，免费代理却往往缺乏此类保证，使其容易遭受窃听或内容篡改等恶意活动。此外，还存在一个鼓励利用设备安装代理的市场。在本文中，我们提出了一项为期30个月的纵向研究，分析我们从11家提供商收集的免费Web代理的稳定性、安全性和潜在操纵行为。我们的收集产生了超过640,600个代理，并对其进行累计每日测试。我们发现，在测试期间仅有34.5%的代理至少活跃过一次，这表明免费代理普遍不稳定。从地理上看，大多数代理来自美国和中国。借助Shodan搜索引擎，我们在代理的IP地址上识别出4,452个不同漏洞，其中包括1,755个允许未经授权远程代码执行的漏洞，以及2,036个可在主机设备上实现权限提升的漏洞。通过对代理IP地址进行软件分析，我们发现其中42,206个似乎运行在MikroTik路由器上。令人担忧的是，我们还发现16,923个代理会篡改内容，表明代理所有者可能具有恶意意图。最终，我们的研究揭示，使用免费Web代理会给用户的隐私和安全带来重大风险。我们的分析所揭示的不稳定性、漏洞以及恶意行为的可能性，使我们强烈告诫用户不要依赖免费代理。
英文摘要：
Free-proxies have been widespread since the early days of the Web, helping users bypass geo-blocked content and conceal their IP addresses. Various proxy providers promise faster Internet or increased privacy while advertising their lists comprised of hundreds of readily available free proxies. However, while paid proxy services advertise the support of encrypted connections and high stability, free proxies often lack such guarantees, making them prone to malicious activities such as eavesdropping or modifying content. Furthermore, there is a market that encourages exploiting devices to install proxies. In this paper, we present a 30-month longitudinal study analyzing the stability, security, and potential manipulation of free web proxies that we collected from 11 providers. Our collection resulted in over 640,600 proxies, that we cumulatively tested daily. We find that only 34.5% of proxies were active at least once during our tests, showcasing the general instability of free proxies. Geographically, a majority of proxies originate from the US and China. Leveraging the Shodan search engine, we identified 4,452 distinct vulnerabilities on the proxies' IP addresses, including 1,755 vulnerabilities that allow unauthorized remote code execution and 2,036 that enable privilege escalation on the host device. Through the software analysis on the proxies' IP addresses, we find that 42,206 of them appear to run on MikroTik routers. Worryingly, we also discovered 16,923 proxies that manipulate content, indicating potential malicious intent by proxy owners. Ultimately, our research reveals that the use of free web proxies poses significant risks to users' privacy and security. The instability, vulnerabilities, and potential for malicious actions uncovered in our analysis lead us to strongly caution users against relying on free proxies.
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。
