Bun File Disclosure Scanner

Bun is a modern JavaScript runtime and package manager that accelerates development workflows through high-performance module loading and installation. It is primarily used by developers to manage dependencies in JavaScript projects, enabling them to ensure consistent and efficient application builds. Bun's lock files, such as bun.lockb, are critical for maintaining the integrity and reliability of dependencies across different environments. This lock file acts as a counterpart to package-lock.json and yarn.lock, aiming to create smoother and more reproducible dependency installation processes. The software's growing popularity in the Node.js ecosystem makes it a frequent choice for developers seeking speed and simplicity. Users typically deploy Bun in development and production environments to streamline dependency management and boost execution speeds.

The File Disclosure vulnerability identified in this scanner pertains to the unprotected exposure of the bun.lockb file. This file, integral to Bun's dependency management functionality, can inadvertently be accessible to unauthorized users if not properly secured. Such exposure may reveal sensitive information about the project's dependency versions and structures. The scanner checks for the presence of bun.lockb in accessible paths, assessing whether it can be freely accessed without appropriate authentication controls. Understanding the risk of disclosing lock files is crucial, as it may provide attackers with insights into the project's configuration that could be exploited. This vulnerability signifies the importance of stringent access controls and secure configuration practices in environments that utilize Bun.

The File Disclosure vulnerability exploits scenarios where the Bun lock file (bun.lockb) is served without proper access restrictions. Vulnerable endpoints include any public or inadequately secured web paths where this file could be exposed. The scanner targets HTTP responses that match specific markers within the file's content suggesting its presence. Additionally, it inspects HTTP headers to confirm the file type, and verifies a 200 status code indicating successful file retrieval. Technical checks involve detecting specific keywords or formats indicative of the lock file's content and ensuring these elements can be validated as part of HTTP server responses. Failure to secure endpoints serving Bun lock files can result in unauthorized data exposure and potential misuse.

Exploitation of this vulnerability could allow malicious actors to learn about precise software versions and dependency metadata, which might be exploited for further attacks. Such knowledge could assist in orchestrating precise dependency manipulation or version-specific exploits. Unauthorized insight into a project's structure empowers attackers to craft targeted vulnerabilities, potentially harming the integrity and availability of the service. Ensuring that sensitive files like bun.lockb are not indiscriminately exposed mitigates these risks. The potential impact underlines the necessity of robust security policies, emphasizing protective access controls.

REFERENCES

• https://bun.sh/docs/install/lockfile