Software ecosystems like Maven Central play a crucial role in modern software supply chains by providing repositories for libraries and build plugins. However, the separation between binaries and their corresponding source code in Maven Central presents a significant challenge, particularly when it comes to linking binaries back to their original build environment. This lack of transparency poses security risks, as approximately 84% of the top 1200 commonly used artifacts are not built using a transparent CI/CD pipeline. Consequently, users must place a significant amount of trust not only in the source code but also in the environment in which these artifacts are built.Rebuilding software artifacts from source provides a robust solution to improve supply chain security. This approach allows for a deeper review of code, verification of binary-source equivalence, and control over dependencies. However, challenges arise due to variations in build environments, such as JDK versions and build commands, which can lead to build failures. Additionally, ensuring that all dependencies are rebuilt from source across large and complex dependency graphs further complicates the process. In this paper, we introduce an extension to Macaron, an industry-grade open-source supply chain security framework, to automate the rebuilding of Maven artifacts from source. Our approach improves upon existing tools, by offering better performance in source code detection and automating the extraction of build specifications from GitHub Actions workflows. We also present a comprehensive root cause analysis of build failures in Java projects and propose a scalable solution to automate the rebuilding of artifacts, ultimately enhancing security and transparency in the open-source supply chain. While we demonstrate our approach for Java, our solution is easily extensible to other languages and ecosystems like Python and npm packages.

Following the advent of the American Fuzzy Lop (AFL), fuzzing had a surge in popularity, and modern day fuzzers range from simple blackbox random input generators to complex whitebox concolic frameworks that are capable of deep program introspection. Web application fuzzers, however, did not benefit from the tremendous advancements in fuzzing for binary programs and remain largely blackbox in nature. In this experience paper, we show how techniques like state-aware crawling, type inference, coverage and taint analysis can be integrated with a black-box fuzzer to find more critical vulnerabilities, faster (speedups between 7.4× and 25.9×). Comparing BackREST against three other web fuzzers on five large (>500 KLOC) Node.js applications shows how it consistently achieves comparable coverage while reporting more vulnerabilities than state-of-the-art. Finally, using BackREST, we uncovered eight 0-days, out of which six were not reported by any other fuzzer. All the 0-days have been disclosed and most are now public, including two in the highly popular Sequelize and Mongodb libraries.