论文标题
隐藏在平坦的视线中：探索Android应用中的加密通道
Hidden in Plain Sight: Exploring Encrypted Channels in Android apps
论文作者
论文摘要
随着Android操作系统中的隐私功能的改善，隐私侵入性应用程序可能会逐渐将其重点转移到非标准和秘密频道上，以泄漏私人用户/设备信息。此类泄漏也很大程度上没有被最新的隐私分析工具所发现的，这些工具在通过常规HTTP和HTTPS渠道发现隐私暴露非常有效。在这项研究中，我们设计和实施了第三眼，以显着扩展当前隐私分析工具的可见性，这是在各种非标准和掩护渠道中发生的暴露，即通过TCP/UDP（超越HTTP/s）以及使用HTTP/s和非HTTP协议的多层定量加密的任何协议（超越HTTP/s）。除了网络暴露外，我们还通过存储媒体考虑秘密渠道，这些媒体也利用自定义加密层。使用第三眼，我们分析了来自Androidrank的各个类别中的12,598个顶级应用程序，发现2887/12,598（22.92％）应用程序使用自定义的加密/解密网络传输和存储在共享设备存储中的网络传输和存储内容，以及这些应用程序的Apps Enterviss Intelling Engection Id ID（E.G. G. G. G. G. G. 85.38％），iD（E.G. G. G. G. G. 85.38％）的应用程序（85.38％）指纹用户。此外，299个应用程序通过HTTP/非HTTP协议传输了不安全的加密内容； 22个使用HTTPS上身份验证令牌的应用程序恰好使它们因不安全（尽管经过自定义加密）的HTTP/非HTTP频道而暴露出来。我们发现了具有多个混淆级别的非标准和掩护通道（例如，通过HTTPS加密数据，嵌套级别的加密），以及使用脆弱的键和加密算法的使用。我们的发现可以为非标准和秘密渠道的不断发展的领域提供宝贵的见解，并有助于刺激新的对策，以防止这种隐私泄漏和安全问题。
As privacy features in Android operating system improve, privacy-invasive apps may gradually shift their focus to non-standard and covert channels for leaking private user/device information. Such leaks also remain largely undetected by state-of-the-art privacy analysis tools, which are very effective in uncovering privacy exposures via regular HTTP and HTTPS channels. In this study, we design and implement, ThirdEye, to significantly extend the visibility of current privacy analysis tools, in terms of the exposures that happen across various non-standard and covert channels, i.e., via any protocol over TCP/UDP (beyond HTTP/S), and using multi-layer custom encryption over HTTP/S and non-HTTP protocols. Besides network exposures, we also consider covert channels via storage media that also leverage custom encryption layers. Using ThirdEye, we analyzed 12,598 top-apps in various categories from Androidrank, and found that 2887/12,598 (22.92%) apps used custom encryption/decryption for network transmission and storing content in shared device storage, and 2465/2887 (85.38%) of those apps sent device information (e.g., advertising ID, list of installed apps) over the network that can fingerprint users. Besides, 299 apps transmitted insecure encrypted content over HTTP/non-HTTP protocols; 22 apps that used authentication tokens over HTTPS, happen to expose them over insecure (albeit custom encrypted) HTTP/non-HTTP channels. We found non-standard and covert channels with multiple levels of obfuscation (e.g., encrypted data over HTTPS, encryption at nested levels), and the use of vulnerable keys and cryptographic algorithms. Our findings can provide valuable insights into the evolving field of non-standard and covert channels, and help spur new countermeasures against such privacy leakage and security issues.
