Mobile devices are used more and more in everyday life. They are our cameras, wallets, and keys. Basically, they embed most of our private information in our pocket. For this and other reasons, mobile devices, and in particular the software that runs on them, are considered first-class citizens in the software-vulnerabilities landscape. Several studies investigated the software-vulnerabilities phenomenon in the context of mobile apps and, more in general, mobile devices. Most of these studies focused on vulnerabilities that could affect mobile apps, while just few investigated vulnerabilities affecting the underlying platform on which mobile apps run: the Operating System (OS). Also, these studies have been run on a very limited set of vulnerabilities. In this paper we present the largest study at date investigating Android-related vulnerabilities, with a specific focus on the ones affecting the Android OS. In particular, we (i) define a detailed taxonomy of the types of Android-related vulnerability, (ii) investigate the layers and subsystems from the Android OS affected by vulnerabilities, and (iii) study the survivability of vulnerabilities (i.e., the number of days between the vulnerability introduction and its fixing). Our findings could help OS and apps developers in focusing their verification & validation activities, and researchers in building vulnerability detection tools tailored for the mobile world.

An empirical study on Android-related vulnerabilities

With the introduction of Android 5 Lollipop, the Android Runtime (ART) superseded the Dalvik Virtual Machine (DVM) by introducing ahead-of-time compilation and native execution of applications, effectively deprecating seminal works such as TaintDroid that hitherto depend on the DVM. In this paper, we discuss alternatives to overcome those restrictions and highlight advantages for the security community that can be derived from ART's novel on-device compiler dex2oat and its accompanying runtime components. To this end, we introduce ARTist, a compiler-based application instrumentation solution for Android that does not depend on operating system modifications and solely operates on the application layer. Since dex2oat is yet uncharted, our approach required first and foremost a thorough study of the compiler suite's internals and in particular of the new default compiler backend called Optimizing. We document the results of this study in this paper to facilitate independent research on this topic and exemplify the viability of ARTist by realizing two use cases. In particular, we conduct a case study on whether taint tracking can be re-instantiated using a compiler-based app instrumentation framework. Overall, our results provide compelling arguments for the community to choose compiler-based approaches over alternative bytecode or binary rewriting approaches for security solutions on Android.

ARTist: The Android Runtime Instrumentation and Security Toolkit

We present ARTist, a compiler-based application instrumentation solution for Android. ARTist is based on the new ART runtime and the on-device dex2oat compiler of Android, which replaced the interpreter-based managed runtime (DVM) from Android version 5 onwards. Since dex2oat is yet uncharted, our approach required first and foremost a thorough study of the compiler suite's internals and in particular of the new default compiler backend Optimizing. We document the results of this study in this paper to facilitate independent research on this topic and exemplify the viability of ARTist by realizing two use cases. Moreover, given that seminal works like TaintDroid hitherto depend on the now abandoned DVM, we conduct a case study on whether taint tracking can be re-instantiated using a compiler-based instrumentation framework. Overall, our results provide compelling arguments for preferring compiler-based instrumentation over alternative bytecode or binary rewriting approaches.

Dynamic taint analysis (DTA), as a mainstream information flow tracking technique, has been widely used in mobile security. On the Android platform, the existing DTA approaches are typically implemented by instrumenting the Dalvik virtual machine (DVM) interpreter or the Android emulator with taint enforcement code. The most prominent problem of the interpreter-based approaches is that they cannot work in the new Android RunTime (ART) environment introduced since the 5.0 release. For the emulator-based approaches, the most prominent problem is that they cannot be deployed on real devices. In addition, almost all the existing Android DTA approaches only concern the explicit information flow caused by data dependence, while completely ignore the impact of implicit information flow caused by control dependence. These problems limit their adoption in the latest Android system and make them ineffective in detecting the state-of-the-art malware whose privacy-breaching behaviors are inactivated in the analyzed environment (e.g., the emulator) or conducted via implicit information flow. In this paper, we present TaintMan, an ART-compatible DTA framework that can be deployed on unmodified and non-rooted Android devices. In TaintMan, the taint enforcement code is statically instrumented into both the target application and the system class libraries to track data flow and common control flow. A specially designed execution environment reconstruction technique, named reference hijacking, is proposed to force the target application to reference the instrumented system class libraries. By enforcing on-demand instrumentation and on-demand tracking, the performance overhead is significantly reduced. We have developed TaintMan and deployed it on two popular stock smartphones (HTC One S equipped with Android-4.0 and Motorola MOTO G equipped with Android-5.0). The evaluation with malware samples and real-world applications shows that TaintMan can effectively detect privacy leakage behaviors with an acceptable performance overhead.

TaintMan: an ART-Compatible Dynamic Taint Analysis Framework on Unmodified and Non-Rooted Android Devices

The Android ecosystem today is a growing universe of a few billion devices, hundreds of millions of users and millions of applications targeting a wide range of activities where sensitive information is collected and processed. Security of communication and privacy of data are thus of utmost importance in application development. Yet, regularly, there are reports of successful attacks targeting Android users. While some of those attacks exploit vulnerabilities in the Android operating system, others directly concern application-level code written by a large pool of developers with varying experience. Recently, a number of studies have investigated this phenomenon, focusing, however, only on a specific vulnerability type appearing in apps, and based on only a snapshot of the situation at a given time. Thus, the community is still lacking comprehensive studies exploring how vulnerabilities have evolved over time, and how they evolve in a single app across developer updates. Our work fills this gap by leveraging a data stream of 5 million app packages to reconstruct versioned lineages of Android apps, and finally, obtained 28 564 app lineages (i.e., successive releases of the same Android apps) with more than ten app versions each, corresponding to a total of 465 037 apks. Based on these app lineages, we apply state-of-the-art vulnerability-finding tools and investigate systematically the reports produced by each tool. In particular, we study which types of vulnerabilities are found, how they are introduced in the app code, where they are located, and whether they foreshadow malware. We provide insights based on the quantitative data as reported by the tools, but we further discuss the potential false positives. Our findings and study artifacts constitute a tangible knowledge to the community. It could be leveraged by developers to focus verification tasks, and by researchers to drive vulnerability discovery and repair research efforts.

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Understanding the Evolution of Android App Vulnerabilities

Furmonertinib (AST2818) versus gefitinib as first-line therapy for Chinese patients with locally advanced or metastatic EGFR mutation-positive non-small-cell lung cancer (FURLONG): a multicentre, double-blind, randomised phase 3 study.

Many efforts have been paid to enhance the security of Android. However, less attention has been given to how to practically adopt the enhancements on off-the-shelf devices. In particular, securing Android devices often requires modifying their write-protected underlying system component files (especially the system libraries) by flashing or rooting devices, which is unacceptable in many realistic cases. In this paper, a novel technique, called reference hijacking, is presented to address the problem. By introducing a specially designed reset procedure, a new execution environment is constructed for the target application, in which the reference to the underlying system libraries will be redirected to the security-enhanced alternatives. The technique can be applicable to both the Dalvik and Android Runtime (ART) environments and to almost all mainstream Android versions (2.x to 5.x). To demonstrate the capability of reference hijacking, we develop three prototype systems, PatchMan, ControlMan, and TaintMan, to enforce specific security enhancements, involving patching vulnerabilities, protecting inter-component communications, and performing dynamic taint analysis for the target application. These three prototypes have been successfully deployed on a number of popular Android devices from different manufacturers, without modifying the underlying system. The evaluation results show that they are effective and do not introduce noticeable overhead. They strongly support that reference hijacking can substantially improve the practicability of many security enhancement efforts for Android.

Reference hijacking: patching, protecting and analyzing on unmodified and non-rooted android devices

Central nervous system efficacy of furmonertinib (AST2818) versus gefitinib as first-line treatment for EGFR mutated non-small cell lung cancer: results from the FURLONG study.

A Study on the Impact of Pilot Free Trade Zones on Regional Technological Innovation and Spatial Spillover Effects

Abstract Background Renal ischemia–reperfusion injury (IRI) is one reason for renal transplantation failure. Recent studies have shown that mitochondrial dynamics is closely related to IRI, and that inhibition or reversal of mitochondrial division protects organs against IRI. Optic atrophy protein 1 (OPA1), an important factor in mitochondrial fusion, has been shown to be upregulated by sodium-glucose cotransporter 2 inhibitor (SGLT2i). Also, the antiinflammatory effects of SGLT2i have been demonstrated in renal cells. Thus, we hypothesized that empagliflozin could prevent IRI through inhibiting mitochondrial division and reducing inflammation. Methods Using hematoxylin–eosin staining, enzyme linked immunosorbent assay (ELISA), flow cytometry, immunofluorescent staining, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) staining, real-time PCR, RNA-sequencing, and western blot, we analyzed renal tubular tissue from in vivo and in vitro experiments. Results Through animal experiments and sequencing analysis, we first confirmed the protection against IRI and the regulation of mitochondrial dynamics-related factors and inflammatory factors by empagliflozin pretreatment. Then, through hypoxia/reoxygenation (H/R) cellular experiments, we confirmed that empagliflozin could inhibit mitochondrial shortening and division and upregulate OPA1 in human renal tubular epithelial cell line (HK-2) cells. Subsequently, we knocked down OPA1, and mitochondrial division and shortening were observed, which could be alleviated by empagliflozin treatment. Combined with the previous results, we concluded that OPA1 downregulation leads to mitochondrial division and shortening, and empagliflozin can alleviate the condition by upregulating OPA1. We further explored the pathway through which empagliflozin functions. Related studies have shown the activation of AMPK pathway by empagliflozin and the close correlation between the AMPK pathway and OPA1. In our study, we blocked the AMPK pathway, and OPA1 upregulation by empagliflozin was not observed, thus demonstrating the dependence of empagliflozin on the AMPK pathway. Conclusion The results indicated that empagliflozin could prevent or alleviate renal IRI through antiinflammatory effects and the AMPK–OPA1 pathway. Ischemia–reperfusion injury is an inevitable challenge in organ transplantation. It is necessary to develop a new therapeutic strategy for IRI prevention in addition to refining the transplantation process. In this study, we confirmed the preventive and protective effects of empagliflozin in renal ischemia–reperfusion injury. Based on these findings, empagliflozin is promising to be a preventive agent for renal ischemia–reperfusion injury and can be applied for preemptive administration in kidney transplantation. 

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Empagliflozin improves renal ischemia–reperfusion injury by reducing inflammation and enhancing mitochondrial fusion through AMPK–OPA1 pathway promotion

Shuyang Zhu

Papers

Furmonertinib (AST2818) versus gefitinib as first-line therapy for Chinese patients with locally advanced or metastatic EGFR mutation-positive non-small-cell lung cancer (FURLONG): a multicentre, double-blind, randomised phase 3 study.

Reference hijacking: patching, protecting and analyzing on unmodified and non-rooted android devices

Central nervous system efficacy of furmonertinib (AST2818) versus gefitinib as first-line treatment for EGFR mutated non-small cell lung cancer: results from the FURLONG study.

A Study on the Impact of Pilot Free Trade Zones on Regional Technological Innovation and Spatial Spillover Effects

Empagliflozin improves renal ischemia–reperfusion injury by reducing inflammation and enhancing mitochondrial fusion through AMPK–OPA1 pathway promotion