Touchjacking attacks on Web in Android, iOS, and Windows Phone

To make it easy for applications to interact with the Web, most mobile platforms, including Android, iOS, and Windows Phone, provide a mechanism that allows applications to embed a small but powerful browser component inside. This mechanism is called WebView in Android (it is called different names in other platforms). WebView implements a number of APIs that can be used by applications to interact with the web contents inside WebView. It has been pointed out by the previous work that malicious applications can use these APIs to attack the web contents inside WebView. Proposals are made by the previous work to fix the problems of those APIs. We have discovered that by fixing those APIs, WebView is still not secure. This is because the previous work only focuses on the APIs specifically designed for WebView; they have overlooked the APIs that WebView inherits from its super classes. These APIs are designed for the general-purposed user interface (UI) components, and they seem to pose no risk to those components; however, the combination of these APIs with the Web has led to new risks. We have identified several attacks based on these APIs. Our attacks are called Touchjacking attacks. They treat WebView as a blackbox, i.e., they do not use the APIs that are designed specifically for WebView; instead, they only use the inherited APIs. Through these APIs, malicious applications can attack the web contents inside WebView. The impact of the attacks is quite significant, as all the platforms that we have studied, including Android, iOS, and Windows Phone, are vulnerable to these attacks.