Recently, computer vision systems, for example, smart traffic surveillance systems, facial recognition systems, etc., have significantly changed our daily life. Even though the neural networks in such systems are known to suffer from backdoor attacks, causing the backdoored models to behave well on benign samples but maliciously on controlled samples (with triggers applied to activate the backdoor), it is generally believed that most of the triggers, when used in physical attacks, are noticeable to victim users and not robust in various settings, such as different angles, distances, lighting conditions, etc. In this paper, we leverage electromagnetic interference (EMI) to produce a specific pattern distortion in images captured by the camera system and utilize the pattern distortion as the backdoor trigger. To avoid the overhead of manually collecting poisoned images, we introduce a simulation sample generation approach, converting clean images to poisoned ones by simulating the distortion caused by EMI against the camera system. Additionally, we propose a contrast loss function to enhance the generalization of backdoor features, improving triggers’ capability to activate the embedded backdoors. We conduct extensive physical experiments using diverse deep neural networks across various camera systems in different practical environments, achieving a 92.54% average backdoor success rate.

Ever since its initial release in 2008, the Android OS has rapidly grown to become the world’s most widely used mobile OS. Mobile vendors extend the Android Open Source Project (AOSP) led by Google to customize their own Android variants. With the AOSP releasing new versions frequently, vendors need to periodically carry out Android upgrades that integrate the latest code changes from AOSP into their Android variants. Both the AOSP and Android variants independently undergo complex modifications. Consequently, Android upgrades often lead to merge conflicts caused by competing changes to the same code line. Vendors have devoted significant effort to understanding and resolving these problems. Despite extensive research on Android upgrades and merge conflicts, there is little understanding of the conflict-related activities performed in Android upgrade practice, and the corresponding challenges faced by practitioners . In this study, we employed a qualitative research methodology involving questionnaires with 120 practitioners and interviews with a leading Android vendor to explore the challenges and improvement opportunities. Our investigation demonstrates that the Android upgrade process is fundamentally an exercise in architectural evolution, necessitating the adoption of architectural thinking rather than relying on mere code-level patches to systematically address upgrade-induced challenges. We have identified challenges at different stages of Android upgrade implementation, including baseline analysis, conflict reason analysis, conflict resolution, and conflict impact analysis. Our findings indicate opportunities for enhancing the Android upgrade practice, particularly in documentation, management, refactoring activities, and team collaboration. Additionally, we outline future research directions from an architectural perspective. We envision that our study can benefit software ecosystems where customized downstream derivatives need to maintain co-evolution with their upstream core.

In recent years, tremendous success has been witnessed in Retrieval-Augmented Generation (RAG), widely used to enhance Large Language Models (LLMs) in domain-specific, knowledge-intensive, and privacy-sensitive tasks. However, attackers may steal those valuable RAGs and deploy or commercialize them, making it essential to detect Intellectual Property (IP) infringement. Most existing ownership protection solutions, such as watermarks, are designed for relational databases and texts. They cannot be directly applied to RAGs because relational database watermarks require white-box access to detect IP infringement, which is unrealistic for the knowledge base in RAGs. Meanwhile, post-processing by the adversary's deployed LLMs typically destructs text watermark information. To address those problems, we propose a novel black-box ''knowledge watermark'' approach, named RAG-WM, to detect IP infringement of RAGs. RAG-WM uses a multi-LLM interaction framework, comprising a Watermark Generator, Shadow LLM & RAG, and Watermark Discriminator, to create watermark texts based on watermark entity-relationship tuples and inject them into the target RAG. We evaluate RAG-WM across three domain-specific and two privacy-sensitive tasks on four benchmark LLMs. Experimental results show that RAG-WM effectively detects the stolen RAGs in various deployed LLMs. Furthermore, RAG-WM is robust against paraphrasing, unrelated content removal, knowledge insertion, and knowledge expansion attacks. Lastly, RAG-WM can also evade watermark detection approaches, highlighting its promising application in detecting IP infringement of RAG systems.

Phone vendors customize their Android variants to enhance system functionalities based on the Android Open Source Project (AOSP). While independent development, Android variants have to periodically evolve with the upstream AOSP and merge code changes from AOSP. Vendors have invested great effort to maintain their variants and resolve merging conflicts. In this paper, we characterize the design smells with recurring patterns that break the design boundary between Android variants and AOSP. These smells are manifested as problematic dependencies across the boundary, hindering Android variants' maintainability and co-evolution with AOSP. We propose the DroidDS for automatically detecting design smells. We collect 22 Android variant versions and 22 corresponding AOSP versions, involving 4 open-source projects and 1 industrial project. Our results demonstrate that: files involved in design smells consume higher maintenance costs than other files; these infected files are not merely the files with large code size, increased complexity, and object-oriented smells; the infected files have been involved in more than half of code conflicts induced by re-applying AOSP's changes to Android variants; a substantial portion of design issues could be mitigable. Practitioners can utilize our DroidDS to pinpoint and prioritize design problems for Android variants. Refactoring these problems will help keep a healthy coupling between diverse variants and AOSP, potentially improving maintainability and reducing conflict risks.

Near Field Communication (NFC) has been widely used for rapid data exchange between electronic devices over a very short distance. In this paper, we reveal a new security vulnerability in NFC passive communication channels where transferred data can be modified in real-time. The security threat of data modification posed by this vulnerability is called NFCEraser. Exploiting electromagnetic interference (EMI), NFCEraser injects signals into the crystal oscillator’s electrode and adjusts the amplitude of carrier signals in NFC communication channels. By manipulating the parameters of EMI signals, NFCEraser is able to arbitrarily flip the bits in data payload sent from an NFC peer device, which may cause serious security outcomes. To assess the severity of NFCEraser, we examine six NFC modules under NFC-A/B communication modes and successfully perform reading operations under a variety of data lengths. The experimental results show that NFCEraser can modify data bits in response frames from NFC peer devices with the maximum 89% accuracy, under around 0.21μs latency. Our analysis further shows that NFCEraser can maintain an attack success rate of no less than 85% in environments with typical levels of electromagnetic noise.