Biblio

The rising popularity of Android and the GUI-driven nature of its apps have motivated the need for applicable automated GUI testing techniques. Although exhaustive testing of all possible combinations is the ideal upper bound in combinatorial testing, it is often infeasible, due to the combinatorial explosion of test cases. This paper presents TrimDroid, a framework for GUI testing of Android apps that uses a novel strategy to generate tests in a combinatorial, yet scalable, fashion. It is backed with automated program analysis and formally rigorous test generation engines. TrimDroid relies on program analysis to extract formal specifications. These speci- fications express the app’s behavior (i.e., control flow between the various app screens) as well as the GUI elements and their dependencies. The dependencies among the GUI elements comprising the app are used to reduce the number of combinations with the help of a solver. Our experiments have corroborated TrimDroid’s ability to achieve a comparable coverage as that possible under exhaustive GUI testing using significantly fewer test cases.

Given the ever increasing number of research tools to automatically generate inputs to test Android applications (or simply apps), researchers recently asked the question "Are we there yet?" (in terms of the practicality of the tools). By conducting an empirical study of the various tools, the researchers found that Monkey (the most widely used tool of this category in industrial settings) outperformed all of the research tools in the study. In this paper, we present two signi cant extensions of that study. First, we conduct the rst industrial case study of applying Monkey against WeChat, a popular  messenger app with over 762 million monthly active users, and report the empirical ndings on Monkey's limitations in an industrial setting. Second, we develop a new approach to address major limitations of Monkey and accomplish substantial code-coverage improvements over Monkey. We conclude the paper with empirical insights for future enhancements to both Monkey and our approach.

Smart devices from smartphones to wearable computers today have been used in many purposes. These devices run various mobile operating systems like Android, iOS, Symbian, Windows Mobile, etc. Since the mobile devices are widely used and contain personal information, they are subject to security attacks by mobile malware applications. In this work we propose a new approach based on control flow graphs and machine learning algorithms for static Android malware analysis. Experimental results have shown that the proposed approach achieves a high classification accuracy of 96.26% in general and high detection rate of 99.15% for DroidKungfu malware families which are very harmful and difficult to detect because of encrypting the root exploits, by reducing data dimension significantly for real time analysis.

The popularity of Android OS has dramatically increased malware apps targeting this mobile OS. The daily amount of malware has overwhelmed the detection process. This fact has motivated the need for developing malware detection and family attribution solutions with the least manual intervention. In response, we propose Cypider framework, a set of techniques and tools aiming to perform a systematic detection of mobile malware by building an efficient and scalable similarity network infrastructure of malicious apps. Our detection method is based on a novel concept, namely malicious community, in which we consider, for a given family, the instances that share common features. Under this concept, we assume that multiple similar Android apps with different authors are most likely to be malicious. Cypider leverages this assumption for the detection of variants of known malware families and zero-day malware. It is important to mention that Cypider does not rely on signature-based or learning-based patterns. Alternatively, it applies community detection algorithms on the similarity network, which extracts sub-graphs considered as suspicious and most likely malicious communities. Furthermore, we propose a novel fingerprinting technique, namely community fingerprint, based on a learning model for each malicious community. Cypider shows excellent results by detecting about 50% of the malware dataset in one detection iteration. Besides, the preliminary results of the community fingerprint are promising as we achieved 87% of the detection.

In this work we present a study that evaluates and compares two block ciphers, AES and PRESENT, in the context of lightweight cryptography for smartphones security applications. To the best of our knowledge, this is the first comparison between these ciphers using a smartphone as computing platform. AES is the standard for symmetric encryption and PRESENT is one of the first ultra-lightweight ciphers proposed in the literature and included in the ISO/IEC 29192-2. In our study, we consider execution time, voltage consumption and memory usage as metrics for comparison purposes. The two block ciphers were evaluated through several experiments in a low-cost smartphone using Android built in tools. From the results we conclude that, for general purpose encryption AES performs statistically better although block-to-block PRESENT delivers better results.

Android malware is becoming very effective in evading detection techniques, and traditional malware detection techniques are demonstrating their weaknesses. Signature based detection shows at least two drawbacks: first, the detection is possible only after the malware has been identified, and the time needed to produce and distribute the signature provides attackers with window of opportunities for spreading the malware in the wild. For solving this problem, different approaches that try to characterize the malicious behavior through the invoked system and API calls emerged. Unfortunately, several evasion techniques have proven effective to evade detection based on system and API calls. In this paper, we propose an approach for capturing the malicious behavior in terms of device resource consumption (using a thorough set of features), which is much more difficult to camouflage. We describe a procedure, and the corresponding practical setting, for extracting those features with the aim of maximizing their discriminative power. Finally, we describe the promising results we obtained experimenting on more than 2000 applications, on which our approach exhibited an accuracy greater than 99%.

Mobile apps often collect and share personal data with untrustworthy third-party apps, which may lead to data misuse and privacy violations. Most of the collected data originates from sensors built into the mobile device, where some of the sensors are treated as sensitive by the mobile platform while others permit unconditional access. Examples of privacy-prone sensors are the microphone, camera and GPS system. Access to these sensors is always mediated by protected function calls. On the other hand, the light sensor, accelerometer and gyroscope are considered innocuous. All apps have unrestricted access to their data. Unfortunately, this gap is not always justified. State-of-the-art privacy mechanisms on Android provide inadequate access control and do not address the vulnerabilities that arise due to unmediated access to so-called innocuous sensors on smartphones. We have developed techniques to demonstrate these threats. As part of our demonstration, we illustrate possible attacks using the innocuous sensors on the phone. As a solution, we present ipShield, a framework that provides users with greater control over their resources at runtime so as to protect against such attacks. We have implemented ipShield by modifying the AOSP.

The concept of digital right management (DRM) has become extremely important in current mobile environments. This paper shows how partial bitstream encryption can allow the secure distribution of hardware applications resembling the mechanisms of traditional software DRM. Building on the recent developments towards the secure distribution of hardware cores, the paper demonstrates a prototypical implementation of a user mobile device supporting such distribution mechanisms. The prototype extends the Android operating system with support for hardware reconfigurability and showcases the interplay of novel security concepts enabled by hardware DRM, the advantages of a design flow based on high-level synthesis, and the opportunities provided by current software-rich reconfigurable Systems-on-Chips. Relying on this prototype, we also collected extensive quantitative results demonstrating the limited overhead incurred by the secure distribution architecture.

The success or failure of a mobile application (`app') is largely determined by user ratings. Users frequently make their app choices based on the ratings of apps in comparison with similar, often competing apps. Users also expect apps to continually provide new features while maintaining quality, or the ratings drop. At the same time apps must also be secure, but is there a historical trade-off between security and ratings? Or are app store ratings a more all-encompassing measure of product maturity? We used static analysis tools to collect security-related metrics in 38,466 Android apps from the Google Play store. We compared the rate of an app's permission misuse, number of requested permissions, and Androrisk score, against its user rating. We found that high-rated apps have statistically significantly higher security risk metrics than low-rated apps. However, the correlations are weak. This result supports the conventional wisdom that users are not factoring security risks into their ratings in a meaningful way. This could be due to several reasons including users not placing much emphasis on security, or that the typical user is unable to gauge the security risk level of the apps they use everyday.

Privacy-preserving range queries allow encrypting data while still enabling queries on ciphertexts if their corresponding plaintexts fall within a requested range. This provides a data owner the possibility to outsource data collections to a cloud service provider without sacrificing privacy nor losing functionality of filtering this data. However, existing methods for range queries either leak additional information (like the ordering of the complete data set) or slow down the search process tremendously by requiring to query each ciphertext in the data collection. We present a novel scheme that only leaks the access pattern while supporting amortized poly-logarithmic search time. Our construction is based on the novel idea of enabling the cloud service provider to compare requested range queries. By doing so, the cloud service provider can use the access pattern to speed-up search time for range queries in the future. On the one hand, values that have fallen within a queried range, are stored in an interactively built index for future requests. On the other hand, values that have not been queried do not leak any information to the cloud service provider and stay perfectly secure. In order to show its practicability we have implemented our scheme and give a detailed runtime evaluation.

Maintaining a clean and hygienic civic environment is an indispensable yet formidable task, especially in developing countries. With the aim of engaging citizens to track and report on their neighborhoods, this paper presents a novel smartphone app, called SpotGarbage, which detects and coarsely segments garbage regions in a user-clicked geo-tagged image. The app utilizes the proposed deep architecture of fully convolutional networks for detecting garbage in images. The model has been trained on a newly introduced Garbage In Images (GINI) dataset, achieving a mean accuracy of 87.69%. The paper also proposes optimizations in the network architecture resulting in a reduction of 87.9% in memory usage and 96.8% in prediction time with no loss in accuracy, facilitating its usage in resource constrained smartphones.

As mobile devices increasingly become bigger in terms of display and reliable in delivering paid entertainment and video content, we also see a rise in the presence of mobile applications that attempt to profit by streaming pirated content to unsuspected end-users. These applications are both paid and free and in the case of free applications, the source of funding appears to be advertisements that are displayed while the content is streamed to the device. In this paper, we assess the extent of content copyright infringement for mobile markets that span multiple platforms (iOS, Android, and Windows Mobile) and cover both official and unofficial mobile markets located across the world. Using a set of search keywords that point to titles of paid streaming content, we discovered 8,592 Android, 5,550 iOS, and 3,910 Windows mobile applications that matched our search criteria. Out of those applications, hundreds had links to either locally or remotely stored pirated content and were not developed, endorsed, or, in many cases, known to the owners of the copyrighted contents. We also revealed the network locations of 856,717 Uniform Resource Locators (URLs) pointing to back-end servers and cyber-lockers used to communicate the pirated content to the mobile application.

Android is the most popular platform for mobile devices. It facilitates sharing of data and services among applications using a rich inter-app communication system. While access to resources can be controlled by the Android permission system, enforcing permissions is not sufficient to prevent security violations, as permissions may be mismanaged, intentionally or unintentionally. Android's enforcement of the permissions is at the level of individual apps, allowing multiple malicious apps to collude and combine their permissions or to trick vulnerable apps to perform actions on their behalf that are beyond their individual privileges. In this paper, we present COVERT, a tool for compositional analysis of Android inter-app vulnerabilities. COVERT's analysis is modular to enable incremental analysis of applications as they are installed, updated, and removed. It statically analyzes the reverse engineered source code of each individual app, and extracts relevant security specifications in a format suitable for formal verification. Given a collection of specifications extracted in this way, a formal analysis engine (e.g., model checker) is then used to verify whether it is safe for a combination of applications-holding certain permissions and potentially interacting with each other-to be installed together. Our experience with using COVERT to examine over 500 real-world apps corroborates its ability to find inter-app vulnerabilities in bundles of some of the most popular apps on the market.

Smart home automation and IoT promise to bring many advantages but they also expose their users to certain security and privacy vulnerabilities. For example, leaking the information about the absence of a person from home or the medicine somebody is taking may have serious security and privacy consequences for home users and potential legal implications for providers of home automation and IoT platforms. We envision that a new ecosystem within an existing smartphone ecosystem will be a suitable platform for distribution of apps for smart home and IoT devices. Android is increasingly becoming a popular platform for smart home and IoT devices and applications. Built-in security mechanisms in ecosystems such as Android have limitations that can be exploited by malicious apps to leak users' sensitive data to unintended recipients. For instance, Android enforces that an app requires the Internet permission in order to access a web server but it does not control which servers the app talks to or what data it shares with other apps. Therefore, sub-ecosystems that enforce additional fine-grained custom policies on top of existing policies of the smartphone ecosystems are necessary for smart home or IoT platforms. To this end, we have built a tool that enforces additional policies on inter-app interactions and permissions of Android apps. We have done preliminary testing of our tool on three proprietary apps developed by a future provider of a home automation platform. Our initial evaluation demonstrates that it is possible to develop mechanisms that allow definition and enforcement of custom security policies appropriate for ecosystems of the like smart home automation and IoT.

The security of Android depends on the timely delivery of updates to fix critical vulnerabilities. In this paper we map the complex network of players in the Android ecosystem who must collaborate to provide updates, and determine that inaction by some manufacturers and network operators means many handsets are vulnerable to critical vulnerabilities. We define the FUM security metric to rank the performance of device manufacturers and network operators, based on their provision of updates and exposure to critical vulnerabilities. Using a corpus of 20 400 devices we show that there is significant variability in the timely delivery of security updates across different device manufacturers and network operators. This provides a comparison point for purchasers and regulators to determine which device manufacturers and network operators provide security updates and which do not. We find that on average 87.7% of Android devices are exposed to at least one of 11 known critical vulnerabilities and, across the ecosystem as a whole, assign a FUM security score of 2.87 out of 10. In our data, Nexus devices do considerably better than average with a score of 5.17; and LG is the best manufacturer with a score of 3.97.

Pervasiveness of smartphones and the vast number of corresponding apps have underlined the need for applicable automated software testing techniques. A wealth of research has been focused on either unit or GUI testing of smartphone apps, but little on automated support for end-to-end system testing. This paper presents SIG-Droid, a framework for system testing of Android apps, backed with automated program analysis to extract app models and symbolic execution of source code guided by such models for obtaining test inputs that ensure covering each reachable branch in the program. SIG-Droid leverages two automatically extracted models: Interface Model and Behavior Model. The Interface Model is used to find values that an app can receive through its interfaces. Those values are then exchanged with symbolic values to deal with constraints with the help of a symbolic execution engine. The Behavior Model is used to drive the apps for symbolic execution and generate sequences of events. We provide an efficient implementation of SIG-Droid based in part on Symbolic PathFinder, extended in this work to support automatic testing of Android apps. Our experiments show SIG-Droid is able to achieve significantly higher code coverage than existing automated testing tools targeted for Android.

Steganography is a method of hiding information, whereas the goal of cryptography is to make data unreadable. Both of these methodologies have their own advantages and disadvantages. Encrypted messages are easily detectable. If someone is spying on communication channel for encrypted message, he/she can easily identify the encrypted messages. Encryption may draw unnecessary attention to the transferred messages. This may lead to cryptanalysis of the encrypted message if the spy tries to know the message. If the encryption technique is not strong enough, the message may be deciphered. In contrast, Steganography tries to hide the data from third party by smartly embedding the data to some other file which is not at all related to the message. Here care is to be taken to minimize the modification of the container file in the process of embedding data. But the disadvantage of steganography is that it is not as secure as cryptography. In the present method the authors have introduced three-step security. Firstly the secret message is encrypted using bit level columnar transposition method introduced by Nath et al and after that the encrypted message is embedded in some image file along with its size. Finally the modified image is encoded into a QR Code TM. The entire method has also been implemented for the Android mobile environment. This method may be used to transfer confidential message through Android mobile phone.

The threats of smartphone security are mostly from the privacy disclosure and malicious chargeback software which deducting expenses abnormally. They exploit the vulnerabilities of previous permission mechanism to attack to mobile phones, and what's more, it might call hardware to spy privacy invisibly in the background. As the existing Android operating system doesn't support users the monitoring and auditing of system resources, a dynamic supervisory mechanism of process behavior based on Dalvik VM is proposed to solve this problem. The existing android system framework layer and application layer are modified and extended, and special underlying services of system are used to realize a dynamic supervisory on the process behavior of Dalvik VM. Via this mechanism, each process on the system resources and the behavior of each app process can be monitored and analyzed in real-time. It reduces the security threats in system level and positions that which process is using the system resource. It achieves the detection and interception before the occurrence or the moment of behavior so that it protects the private information, important data and sensitive behavior of system security. Extensive experiments have demonstrated the accuracy, effectiveness, and robustness of our approach.

Cryptographic misuse affects a sizeable portion of Android applications. However, there is only an empirical study that has been made about this problem. In this paper, we perform a systematic analysis on the cryptographic misuse, build the cryptographic misuse vulnerability model and implement a prototype tool Crypto Misuse Analyser (CMA). The CMA can perform static analysis on Android apps and select the branches that invoke the cryptographic API. Then it runs the app following the target branch and records the cryptographic API calls. At last, the CMA identifies the cryptographic API misuse vulnerabilities from the records based on the pre-defined model. We also analyze dozens of Android apps with the help of CMA and find that more than a half of apps are affected by such vulnerabilities.
 

Theft or loss of a mobile device could be an information security risk as it can result in loss of con fidential personal data. Traditional cryptographic algorithms are not suitable for resource constrained and handheld devices. In this paper, we have developed an efficient and user friendly tool called “NCRYPT” on Android platform. “NCRYPT” application is used to secure the data at rest on Android thus making it inaccessible to unauthorized users. It is based on lightweight encryption scheme i.e. Hummingbird-2. The application provides secure storage by making use of password based authentication so that an adversary cannot access the confidential data stored on the mobile device. The cryptographic key is derived through the password based key generation method PBKDF2 from the standard SUN JCE cryptographic provider. Various tools for encryption are available in the market which are based on AES or DES encryption schemes. Ihe reported tool is based on Hummingbird-2 and is faster than most of the other existing schemes. It is also resistant to most of attacks applicable to Block and Stream Ciphers. Hummingbird-2 has been coded in C language and embedded in Android platform with the help of JNI (Java Native Interface) for faster execution. This application provides choice for en crypting the entire data on SD card or selective files on the smart phone and protect p ersonal or confidential information available in such devices.

Mobile malware threats (e.g., on Android) have recently become a real concern. In this paper, we evaluate the state-of-the-art commercial mobile anti-malware products for Android and test how resistant they are against various common obfuscation techniques (even with known malware). Such an evaluation is important for not only measuring the available defense against mobile malware threats, but also proposing effective, next-generation solutions. We developed DroidChameleon, a systematic framework with various transformation techniques, and used it for our study. Our results on 10 popular commercial anti-malware applications for Android are worrisome: none of these tools is resistant against common malware transformation techniques. In addition, a majority of them can be trivially defeated by applying slight transformation over known malware with little effort for malware authors. Finally, in light of our results, we propose possible remedies for improving the current state of malware detection on mobile devices.

Summary form only given. In this presentation, several issues regarding operating system security will be investigated. The general problems of OS security are to be addressed. We also discuss why we should consider the security aspects of the OS, and when a secure OS is needed. We delve into the topic of secure OS design as well focusing on covert channel analysis. The specific operating systems under consideration include Windows and Android.
 

Mobile platform security solution has become especially important for mobile computing paradigms, due to the fact that increasing amounts of private and sensitive information are being stored on the smartphones' on-device memory or MicroSD/SD cards. This paper aims to consider a comparative approach to the security aspects of the current smartphone systems, including: iOS, Android, BlackBerry (QNX), and Windows Phone.

The paper presents a secure solution that provides VoIP service for mobile users, handling both pre-call and mid-call mobility. Pre-call mobility is implemented using a presence server that acts as a DNS for the moving users. Our approach also detects any change in the attachment point of the moving users and transmits it to the peer entity by in band signaling using socket communications. For true mid-call mobility we also employ buffering techniques that store packets for the duration of the signaling procedure. The solution was implemented for Android devices and it uses ASP technology for the server part.
 

The development of data communications enabling the exchange of information via mobile devices more easily. Security in the exchange of information on mobile devices is very important. One of the weaknesses in steganography is the capacity of data that can be inserted. With compression, the size of the data will be reduced. In this paper, designed a system application on the Android platform with the implementation of LSB steganography and cryptography using TEA to the security of a text message. The size of this text message may be reduced by performing lossless compression technique using LZW method. The advantages of this method is can provide double security and more messages to be inserted, so it is expected be a good way to exchange information data. The system is able to perform the compression process with an average ratio of 67.42 %. Modified TEA algorithm resulting average value of avalanche effect 53.8%. Average result PSNR of stego image 70.44 dB. As well as average MOS values is 4.8.