CVE-2023-23918: Node.js Privilege Escalation Vulnerability via process.mainModule.require()

A recent vulnerability, CVE-2023-23918, was discovered affecting Node.js versions prior to 19.6.1, 18.14.1, 16.19.1, and 14.21.3. This privilege escalation vulnerability allows users with the appropriate knowledge to bypass the experimental Permissions (https://nodejs.org/api/permissions.html) feature in Node.js and gain unauthorized access to modules by utilizing process.mainModule.require(). It should be noted that this vulnerability specifically affects users who have enabled the experimental permissions option using --experimental-policy.

Exploit Details

The privilege escalation occurs when a malicious user exploits the process.mainModule.require() function (part of Node.js' module system) to load unauthorized resources. This bypasses the intended permission checks, which are applied when the --experimental-policy flag is enabled. The following shows a code snippet illustrating this exploitation:

// Exploit: CVE-2023-23918
// Bypass experimental Permissions feature in Node.js using process.mainModule.require()

const targetModule = 'unauthorized-module';

try {
  // Attempt to load target module without proper permissions
  const unauthorizedModule = process.mainModule.require(targetModule);

  console.log(Loaded unauthorized module: ${unauthorizedModule});
} catch (error) {
  console.error(Error occurred while attempting to load unauthorized module: ${error});
}

Upon executing the exploit code, the unauthorized resource will be loaded, bypassing the experimental Permissions feature.

Original References

This vulnerability was initially reported on Node.js Security Blog (https://nodejs.org/en/blog/vulnerability/july-2023-security-releases/) under the title "CVE-2023-23918: Policy bypass vulnerability (High)".

It was later assigned CVE identifier CVE-2023-23918 by the Node.js Security Working Group (https://github.com/nodejs/security-wg/tree/master/vuln), and its details are publicly available on the Node.js GitHub repository.

To mitigate this vulnerability

1. Ensure you are running a secure version of Node.js. Update your Node.js installation to one of the following patched versions:

14.21.3 or later

2. If you are using the experimental Permissions feature, make sure to set proper permissions for your modules, and be cautious when enabling the --experimental-policy flag.

3. Regularly scan your Node.js projects for known vulnerabilities using security tools such as npm audit (https://docs.npmjs.com/cli/v7/commands/npm-audit) or Snyk (https://snyk.io/).

Conclusion

CVE-2023-23918 highlights the importance of keeping your Node.js installations up-to-date and following security best practices. Users who have enabled the experimental Permissions feature should update to the latest secure version of Node.js and carefully configure their resource permissions. Regularly reviewing and addressing security vulnerabilities within your Node.js applications can help prevent potential attacks and data breaches.

Timeline

Published on: 02/23/2023 20:15:00 UTC
Last modified on: 03/16/2023 16:15:00 UTC