As artificial intelligence tools increasingly lower the barrier to entry for software development, a growing concern within the cybersecurity community centers on the potential for a surge in vulnerable code. A new open-source project, pompelmi, aims to address a frequently overlooked attack vector: file uploads. Created by developer Tommaso Bertocchi, pompelmi provides a toolkit designed to help developers secure their applications against malicious files.
Bertocchi explained the impetus behind pompelmi stemmed from a gap in the market for accessible, modern file upload security solutions. “Traditionally, setting up a malware scanner required deep domain expertise and hours of configuration, which often discourages solo developers,” he said. “By making the integration seamless and ‘plug-and-play’ for Node.js environments, I wanted to encourage more developers to secure their applications, ultimately making the web safer.”
While application security often focuses on network connections, user authentication, and API security, Bertocchi argues that file uploads remain a critical, yet underestimated, threat. “File uploads look simple, but they introduce a meaningful security boundary because you’re accepting untrusted, complex inputs into your system,” he stated. The risks extend beyond simply uploading a virus, encompassing potential for unintended execution, denial-of-service attacks through resource-intensive files, and circumvention of basic security checks.
Pompelmi’s architecture is designed for speed and efficiency. The project leverages Node.js streams and configurable buffer limits to analyze file bytes directly in memory during upload, avoiding the performance overhead of writing to disk. “We also leverage ‘magic bytes’ to quickly identify file types; if a file violates a policy (like a ZIP bomb), we terminate the scan instantly before the entire file is even processed,” Bertocchi explained.
The toolkit offers a high degree of flexibility, including integration with YARA rules – a tool used to identify and classify malware samples – and the ability to compose multiple scanners. However, Bertocchi acknowledged the potential for this flexibility to overwhelm developers. To mitigate this, pompelmi includes built-in policy presets and a “Common Heuristics Scanner” that handles common threats like ZIP bombs and invalid MIME types. The project also provides standard YARA recipes and “reason codes” to explain why a file was flagged as malicious, aiming for a “secure-by-default” experience.
Bertocchi emphasized that a layered approach to security is more realistic than attempting to keep pace with every new exploit. “Implementing a strong baseline that addresses common, repeatable failure modes…and then keep the parts that change frequently updated where relevant is a more realistic approach,” he said. Pompelmi aims to provide that baseline, offering features like strict allowlists, server-side type validation, and resource limits.
Currently a solo project, Bertocchi is actively seeking partnerships or backing to scale pompelmi into a more sustainable organization. “Being the sole maintainer allows me the creative freedom to craft swift decisions,” he said, “However, my goal is to build a team and an infrastructure that can provide advanced resources and consistent updates.” He expressed concern about the potential for burnout, a common issue in open-source projects, and the need to ensure the project’s long-term viability.
One unexpected challenge in developing pompelmi, Bertocchi noted, was ensuring compatibility across different Node.js frameworks. Each framework handles file uploads differently, requiring dedicated adapters to provide a consistent experience for developers. “Building pompelmi as a ‘drop-in’ upload protection layer across multiple stacks meant designing a consistent core policy and then maintaining dedicated adapters,” he explained.
