Android is the world's leading mobile operating system, with over three billion active devices. Detecting vulnerabilities and ensuring timely patch deployment are critical to maintaining security. The Android Open Source Project (AOSP) has enhanced the transparency of security updates through Security Patch Levels. However, challenges related to update speed and availability persist. In 2022, Google reported that half of the zero-day vulnerabilities discovered in the wild were variations of vulnerabilities that had already been patched. Recent research mainly highlights delays in update distribution, often attributing them to fragmentation and focusing primarily on flagship devices or limited time-frames. Our approach takes a device-centric perspective to investigate Android update patterns, analyzing 567K security update records from 2014 to 2024, covering 904 distinct devices from six key Original Equipment Manufacturers (OEMs) across 98 countries. Our extensive analysis revealed notable differences in update release timing across OEMs, device types, and regions. Our study also examines documented vulnerabilities and weaknesses, while assessing OEM compliance with Android security guidelines. Our study shows that$\sim$89.7% of vulnerabilities on unpatched Android devices are exploitable without user interaction and with low attack complexity. We also identified delays linked to fragmentation and OEM-specific challenges, and provide actionable insights for improvement.

Ransomware is an increasingly prevalent form of malware targeting end-users, governments, and businesses. As it has evolved, adversaries added new capabilities to their arsenal. We propose a next-generation browser-based ransomware, RøB , which performs its malicious actions via web technologies, File System Access API (FSA) and WebAssembly (Wasm). RøB uses this API through the victims’ browsers; hence, it does not require the victims to download and install malicious binaries. We performed extensive evaluations with three different OSs, 23 file formats, 29 distinct directories, five cloud providers, and four antivirus solutions. Our evaluations show that RøB can encrypt various types of files in the local and cloud-integrated directories, external storage devices, and network-shared folders of victims. Our experiments also reveal that popular cloud solutions, Box Individual and Apple iCloud can be severely affected by RøB . Moreover, we conducted tests with commercial antivirus software such as AVG, Avast, Kaspersky, and Malware Bytes that perform sensitive directory and suspicious behavior monitoring against ransomware. We verified that RøB can evade these antivirus software and encrypt victim files. Moreover, existing ransomware detection solutions in the literature also cannot be a remedy against RøB due to its distinct features. Therefore, in this paper, we also propose RøBguard , a new detection system for RøB -like attacks. RøBguard monitors the web applications that use the FSA API via function hooking and uses a machine learning classifier to detect RøB -like attacks. We implemented a proof of concept version of RøBguard and our evaluation results show that RøBguard can detect RøB -like browser-based ransomware attacks effectively. We also provide future research directions that should be addressed in this domain.

File upload is a critical feature incorporated by a myriad of web applications in an effort to enable users to share and manage their files conveniently. It has been used in many useful services such as file-sharing and social media. While file upload is an essential component of web applications, the lack of rigorous checks on the file name, type, and content of the uploaded files can result in security issues, often referred to as Unrestricted File Upload (UFU). In this study, we analyze the (in)security of popular file upload libraries and real-world applications in the Node.js ecosystem. To automate our analysis, we propose and implement NodeSEC- a tool designed to analyze file upload insecurities in Node.js applications and libraries. NodeSEC generates unique payloads and thoroughly evaluates the application's file upload security against 13 distinct UFU-type attacks. Utilizing NodeSEC, we analyze the most popular file upload libraries and real-world applications in the Node.js ecosystem. Our analysis results reveal that some real-world web applications are vulnerable to UFU attacks and disclose serious security bugs in file upload libraries. As of this writing, we received 19 CVEs and two US-CERT cases for the security issues that we reported. Our findings provide strong evidence that dynamic features of Node.js applications introduce security shortcomings and that web developers should be cautious when implementing file upload features in their applications. Finally, combining our responsible disclosure experience and root cause analysis, we identified the main causes of significant security weaknesses in file uploads in Node.js.

WebAssembly (Wasm) has seen a lot of attention lately as it spreads through the mobile computing domain and becomes the new standard for performance-oriented web development. It has diversified its uses far beyond just web applications by acting as an execution environment for mobile agents, containers for IoT devices, and enabling new serverless approaches for edge computing. Within the numerous uses of Wasm, not all of them are benign. With the rise of Wasm-based cryptojacking malware, analyzing Wasm applications has been a hot topic in the literature, resulting in numerous Wasm-based cryptojacking detection systems. Many of these methods rely on static analysis, which traditionally can be circumvented through obfuscation. However, the feasibility of the obfuscation techniques for Wasm programs has never been investigated thoroughly. In this paper, we address this gap and perform the first look at code obfuscation for Wasm. We apply numerous obfuscation techniques to Wasm programs, and test their effectiveness in producing a fully obfuscated Wasm program. Particularly, we obfuscate both benign Wasm-based web applications and cryptojacking malware instances and feed them into a state-of-the-art Wasm cryptojacking detector to see if current Wasm analysis methods can be subverted with obfuscation. Our analysis shows that obfuscation can be highly effective and can cause even a state-of-the-art detector to misclassify the obfuscated Wasm samples.