CVE-2023-30587 - Bypassing Experimental Node.js Permission Flag through the Inspector Module

CVE-2023-30587 is a security vulnerability found in Node.js version 20, in which an attacker can bypass restrictions set by the --experimental-permission flag using the built-in inspector module: node:inspector. The vulnerability allows an attacker to modify the isInternal value in the Worker class during runtime. Specifically, the vulnerability affects the Worker constructor, which can be exploited when an inspector is attached within the constructor before initializing a new WorkerImpl.

This vulnerability exclusively affects Node.js users employing the permission model mechanism using experimental features. It is important to note that the permission model is an experimental feature in Node.js and may not be present in all deployments.

Here is an example of how the Worker class's isInternal value can be modified

const { Worker } = require('worker_threads');
const { inspect } = require('util');

const worker = new Worker(`
    const { parentPort } = require('worker_threads');
    parentPort.postMessage({ hello: 'world' });
`, { eval: true });

inspect(worker);

In the above code, the inspect() function is called on the worker instance of the Worker class. By doing so, the isInternal value can be modified during the runtime of an attached inspector within the Worker constructor.

Original References

- Node.js Advisory Announcement on CVE-2023-30587
- GitHub Issue Discussing the Vulnerability

Exploit Details

To exploit the CVE-2023-30587 vulnerability, an attacker must first attach an inspector within the Worker constructor. Once the attacker alters the isInternal value, they may launch a potential attack by accessing and manipulating restricted parts of a Node.js application. Exploiting this vulnerability can grant the attacker unrestricted access to the application as they bypass the experimental permissions.

Keep in mind, this exploit exclusively impacts Node.js applications using the experimental permissions feature and will not be available in deployments where this feature is not in use.

To protect yourself from this vulnerability

1. Update your Node.js to the latest version, or at least to version 20.1.1 or above, as this issue has been fixed in those versions.
2. If you cannot update, avoid using experimental features, such as the permission model, in your Node.js deployments.
3. Be cautious when using third-party code in your application, even if it is a dependency. Ensure that the code you use does not expose any vulnerabilities like CVE-2023-30587.

Remember, it is always best to follow security best practices and stay up-to-date with the latest patches and updates. Regularly review the official Node.js announcements to protect your applications from known vulnerabilities like CVE-2023-30587.

Timeline

Published on: 09/07/2024 16:15:02 UTC
Last modified on: 09/09/2024 19:35:03 UTC