Beware of Path Traversal Attacks on Node.js Experimental Permission Model

CVSScvssV3_0: 7.9

Node.js is a popular JavaScript runtime environment used for building server-side and networking applications. It relies on built-in functions to normalize file paths when accessing the filesystem. However, these functions can be overwritten by malicious code, allowing attackers to bypass the permission model.

Specifically, Node.js versions 20 and 21 contain an experimental permission model that is meant to sandbox apps and restrict which files they can access. But by overwriting the path normalization functions, an attacker could craft file paths that traverse up directories and access files they shouldn’t have access to. This is known as a path traversal attack.

For example, an attacker could try to access “../../sensitive/file” by manipulating the path. If not sanitized properly, it could allow reading files outside the intended sandbox. This compromises the security of the permission model.

To stay protected, Node.js users should avoid enabling experimental features unless they understand the risks. They should also keep their dependencies up-to-date and review any third-party code or modules for security issues. Since the permission model is still in development, extra caution is warranted when using it.

With care and vigilance, Node.js developers can help prevent path traversal attacks and keep their applications secure as this promising new feature continues to evolve. Staying on top of patches and reviews is key to using experimental features safely.