HybridGuard: A Principal-based Permission and Fine-Grained Policy Enforcement Framework for Web-based Mobile Applications

Web-based or hybrid mobile applications (apps) are widely used and supported by various modern hybrid app development frameworks. In this architecture, any JavaScript code, local or remote, can access available APIs, including JavaScript bridges provided by the hybrid framework, to access device resources. This JavaScript inclusion capability is dangerous, since there is no mechanism to determine the origin of the code to control access, and any JavaScript code running in the mobile app can access the device resources through the exposed APIs. Previous solutions are either limited to a particular platform (e.g., Android) or a specific hybrid framework (e.g., Cordova) or only protect the device resources and disregard the sensitive elements in the web environment. Moreover, most of the solutions require the modification of the base platform. In this paper, we present HybridGuard, a novel policy enforcement framework that can enforce principal-based, stateful policies, on multiple origins without modifying the hybrid frameworks or mobile platforms. In HybridGuard, hybrid app developers can specify principal-based permissions, and define fine-grained, and stateful policies that can mitigate a significant class of attacks caused by potentially malicious JavaScript code included from third-party domains, including ads running inside the app. HybridGuard also provides a mechanism and policy patterns for app developers to specify fine-grained policies for multiple principals. HybridGuard is implemented in JavaScript, therefore, it can be easily adapted for other hybrid frameworks or mobile platforms without modification of these frameworks or platforms. We present attack scenarios and report experimental results to demonstrate how HybridGuard can thwart attacks against hybrid mobile apps

Access Control for Plugins in Cordova-Based Hybrid Applications

Hybrid application frameworks such as Cordova allow mobile application (app) developers to create platformindependent apps. The code is written in JavaScript, with special APIs to access device resources in a platform-agnostic way. In this paper, we present a novel app-repackaging attack that repackages hybrid apps with malicious code; this code can exploit Cordova’s plugin interface to tamper with device resources. We further demonstrate a defense against this attack through the use of a novel runtime access control mechanism that restricts access based on the mobile user’s judgement. Our mechanism is easy to introduce to existing Cordova apps, and allows developers to produce apps that are resistant to app-repackaging attacks

MQTT And TCP Socket JavaScript Interface For Hybrid Mobile Applications

Today's needs require portable platforms such as mobile and IoT devices to be used more widely. The mobile platform development industry has grown rapidly as a result of the requirements of today's needs. There are various operating systems available on market such as iOS and Android. Naturally, software companies need to run their applications on multiple operating systems. Therefore, the software companies need to develop a new software with the native programming language of each operating system. Some frameworks like Cordova make possible to develop hybrid applications which based on web technologies and they are able to run on multiple operating systems. In some cases, developers may need to access device resources. In these cases, the developers should develop custom plugin for the hybrid framework. In this study, a plugin for Cordova framework has been developed that allows you to interact between web technologies and MQTT and TCP protocols through the JavaScript API

Web access monitoring mechanism via Android WebView for threat analysis

Many Android apps employ WebView, a component that enables the display of web content in the apps without redirecting users to web browser apps. However, WebView might also be used for cyberattacks. Moreover, to the best of our knowledge, although some countermeasures based on access control have been reported for attacks exploiting WebView, no mechanism for monitoring web access via WebView has been proposed and no analysis results focusing on web access via WebView are available. In consideration of this limitation, we propose a web access monitoring mechanism for Android WebView to analyze web access via WebView and clarify attacks exploiting WebView. In this paper, we present the design and implementation of this mechanism by modifying Chromium WebView without any modifications to the Android framework or Linux kernel. The evaluation results of the performance achieved on introducing the proposed mechanism are also presented here. Moreover, the result of threat analysis of displaying a fake virus alert while browsing websites on Android is discussed to demonstrate the effectiveness of the proposed mechanism

Novel Attacks and Defenses in the Userland of Android

In the last decade, mobile devices have spread rapidly, becoming more and more part of our everyday lives; this is due to their feature-richness, mobility, and affordable price. At the time of writing, Android is the leader of the market among operating systems, with a share of 76% and two and a half billion active Android devices around the world. Given that such small devices contain a massive amount of our private and sensitive information, the economic interests in the mobile ecosystem skyrocketed. For this reason, not only legitimate apps running on mobile environments have increased dramatically, but also malicious apps have also been on a steady rise. On the one hand, developers of mobile operating systems learned from security mistakes of the past, and they made significant strides in blocking those threats right from the start. On the other hand, these high-security levels did not deter attackers. In this thesis, I present my research contribution about the most meaningful attack and defense scenarios in the userland of the modern Android operating system. I have emphasized "userland'' because attack and defense solutions presented in this thesis are executing in the userspace of the operating system, due to the fact that Android is slightly different from traditional operating systems. After the necessary technical background, I show my solution, RmPerm, in order to enable Android users to better protect their privacy by selectively removing permissions from any app on any Android version. This operation does not require any modification to the underlying operating system because we repack the original application. Then, using again repackaging, I have developed Obfuscapk; it is a black-box obfuscation tool that can work with every Android app and offers a free solution with advanced state of the art obfuscation techniques -- especially the ones used by malware authors. Subsequently, I present a machine learning-based technique that focuses on the identification of malware in resource-constrained devices such as Android smartphones. This technique has a very low resource footprint and does not rely on resources outside the protected device. Afterward, I show how it is possible to mount a phishing attack -- the historically preferred attack vector -- by exploiting two recent Android features, initially introduced in the name of convenience. Although a technical solution to this problem certainly exists, it is not solvable from a single entity, and there is the need for a push from the entire community. But sometimes, even though there exists a solution to a well-known vulnerability, developers do not take proper precautions. In the end, I discuss the Frame Confusion vulnerability; it is often present in hybrid apps, and it was discovered some years ago, but I show how it is still widespread. I proposed a methodology, implemented in the FCDroid tool, for systematically detecting the Frame Confusion vulnerability in hybrid Android apps. The results of an extensive analysis carried out through FCDroid on a set of the most downloaded apps from the Google Play Store prove that 6.63% (i.e., 1637/24675) of hybrid apps are potentially vulnerable to Frame Confusion. The impact of such results on the Android users' community is estimated in 250.000.000 installations of vulnerable apps

TLS on Android – Evolution over the last decade

Mobile Geräte und mobile Plattformen sind omnipräsent. Android hat sich zum bedeutendsten mobilen Betriebssystem entwickelt und bietet Milliarden Benutzer:innen eine Plattform mit Millionen von Apps. Diese bieten zunehmend Lösungen für alltägliche Probleme und sind aus dem Alltag nicht mehr wegzudenken. Mobile Apps arbeiten dazu mehr und mehr mit persönlichen sensiblen Daten, sodass ihr Datenverkehr ein attraktives Angriffsziel für Man-in-the-Middle-attacks (MitMAs) ist. Schutz gegen solche Angriffe bieten Protokolle wie Transport Layer Security (TLS) und Hypertext Transfer Protocol Secure (HTTPS), deren fehlerhafter Einsatz jedoch zu ebenso gravierenden Unsicherheiten führen kann. Zahlreiche Ereignisse und frühere Forschungsergebnisse haben diesbezüglich Schwachstellen in Android Apps gezeigt. Diese Arbeit präsentiert eine Reihe von Forschungsbeiträgen, die sich mit der Sicherheit von Android befassen. Der Hauptfokus liegt dabei auf der Netzwerksicherheit von Android Apps. Hierbei untersucht diese Arbeit verschiedene Möglichkeiten zur Verbesserung der Netzwerksicherheit und deren Erfolg, wobei sie die Situation in Android auch mit der generellen Evolution von Netzwerksicherheit in Kontext setzt. Darüber hinaus schließt diese Arbeit mit einer Erhebung der aktuellen Situation und zeigt Möglichkeiten zur weiteren Verbesserung auf.Smart devices and mobile platforms are omnipresent. Android OS has evolved to become the most dominating mobile operating system on the market with billions of devices and a platform with millions of apps. Apps increasingly offer solutions to everyday problems and have become an indispensable part of people’s daily life. Due to this, mobile apps carry and handle more and more personal and privacy-sensitive data which also involves communication with backend or third party services. Due to this, their network traffic is an attractive target for Man-in-the-Middle-attacks (MitMAs). Protection against such attacks is provided by protocols such as Transport Layer Security (TLS) and Hypertext Transfer Protocol Secure (HTTPS). Incorrect use of these, however, can impose similar vulnerabilities lead to equally serious security issues. Numerous incidents and research efforts have featured such vulnerabilities in Android apps in this regard. This thesis presents a line of research addressing security on Android with a main focus on the network security of Android apps. This work covers various approaches for improving network security on Android and investigates their efficacy as well as it puts findings in context with the general evolution of network security in a larger perspective. Finally, this work concludes with a survey of the current state of network security in Android apps and envisions directions for further improvement

Quantitative bounds on the security-critical resource consumption of JavaScript apps

Current resource policies for mobile phone apps are based on permissions that unconditionally grant or deny access to a resource like private data, sensors and services. In reality, the legitimacy of an access may be context-dependent - for example, depending on how often a resource is accessed and in which situation. This thesis presents research into providing bounds on the access of JavaScript apps to security and privacy-relevant resources on mobile devices. The investigated bounds are quantitative and interaction-dependent: for example, permitting one access each time the user presses a specified button. Two novel systems are presented with different approaches to providing these bounds. The system PhoneWrap injects a quantitative policy into an app and enforces the bound dynamically during runtime by monitoring the resource consumption and the user interaction. If the injected bound is exceeded, the resource request is replaced by a deny action. This way, PhoneWrap restricts the unwanted behaviour while the expected functionality can be performed. Policies for this system describe the UI elements which trigger the expected resource consumption and the number of resource units consumed for each interaction. The enforcement of the policies is achieved via wrapping the critical APIs using JavaScript internal features. The injection of a policy can be performed automatically. PhoneWrap is the first system using the lightweight wrapping method to inject policies directly into mobile apps and the first to combine quantitative policies with interaction-dependencies. The second system AmorJiSe statically analyses the resource consumption of a given JavaScript program. This system automatically infers amortised annotations on top of given JavaScript data types. The amortised annotations symbolise reserved resource units stored in the data structures. This way the amount of resource units available to the app is expressed dependent on the size of the data structures. The resulting function types of the UI handlers can be used to extract interaction-dependent bounds. The correctness of these bounds is proven in relation to a resource-aware operational semantics. AmorJiSe extends the known amortised type paradigm to JavaScript with its dynamic object structures and applies this paradigm to the novel domain of mobile resources. Although, the two systems are based on similar resource models and produce similar resource bounds, they use different methods with different properties which are presented in this dissertation