Attacks and Defence on Android Free Floating Windows
Attacks and Defence on Android Free Floating Windows
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DOI：
10.1145/2897845.2897897
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发表时间：
2016-05
期刊：
影响因子：
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通讯作者：
Lingyun Ying;Yao Cheng;Yemian Lu;Yacong Gu;Purui Su;D. Feng
中科院分区：
文献类型：
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作者：
Lingyun Ying;Yao Cheng;Yemian Lu;Yacong Gu;Purui Su;D. Feng
如今，流行的Android与人们的日常生活密切相关，人们依赖Android执行关键操作，并信任Android处理敏感信息。Android系统是一个庞大的系统，其任何一个部分都可能产生潜在的威胁，因此保证Android系统的可用性和安全性至关重要，本文重点研究了自由浮动窗口（Free Floating Window，FF窗口），它是一种可以自由出现在任何其他应用程序之上的窗口。它可以与其他FF窗口、对话框和Activity共享屏幕空间。FF窗口在其外观和行为特征方面都是灵活的。分析了FF窗口的行为特征，包括显示层的优先级和处理用户事件的能力。通过FF窗口的三种类型的攻击，其外观和行为特征的微妙设计被证明，即，针对Android系统的DoS攻击，通过目标重叠劫持GUI，以及使用FF窗口作为侧通道的输入推断。针对FF窗口带来的威胁，设计了FF窗口优先级框架，保护开发者声明的敏感Activity/FF窗口不受任何恶意FF窗口的攻击。提出了一种补充解决方案，以减轻来自恶意活动的混淆攻击。最后，我们为Android提供了如何管理FF窗口的建议。
Nowadays, the popular Android is so closely involved in people's daily lives that people rely on Android to perform critical operations and trust Android with sensitive information. It is of great importance to guarantee the usability and security of Android which, however, is such a huge system that a potential threat may arise from any part of it. In this paper, we focus on the Free Floating window (FF window) which is a category of windows that can appear freely above any other applications. It can share the screen space with other FF windows, dialogs, and activities. An FF window is flexible in both its appearance and behaviour features. We analyse the behaviour features of FF windows, including the priority in display layer and the capability of processing user-generated events. Three types of attacks via FF windows with delicate design in their appearance and behaviour features are demonstrated, i.e., DoS attack against Android system, GUI hijacking by targeting overlap, and input inference using FF windows as a side channel. To address the threat caused by FF windows, we design a priority framework for FF windows, which protects a sensitive activity/FF window declared by developers from being attacked by any malicious FF windows. A complementary solution is proposed to mitigate the confusion attack from malicious activities. Finally, we provide Android with suggestions on how to manage FF windows.