CVE-2023-32004 - Vulnerability in Node.js Experimental Permission Model: Buffer Handling Flaw Leading to Bypass of File Permission Verification

Recently, a vulnerability has been discovered in the experimental permission model of Node.js version 20, specifically related to improper handling of Buffers in the file system APIs. This vulnerability allows for an attacker to traverse paths and bypass the verification of file permissions in the affected Node.js-based applications.

The CVE associated with this vulnerability is CVE-2023-32004. As of now, any user utilizing the experimental permission model in Node.js 20 is at risk.

Please note that at the time this CVE was issued, the permission model is an experimental feature of Node.js, and users are advised to exercise caution when using this feature in production environments.

Technical Details

The flaw lies in the improper handling of Buffers when dealing with file system API calls. The following code snippet demonstrates the improper Buffer handling:

fs.exists('/path/to/some/file', (err, exists) => {
  if (err) console.error(err);
  else console.log('File exists:', exists);
});

The issue occurs when a buffer object is passed instead of a string, making it possible to bypass permission checks. This vulnerability could lead to potential unauthorized file access, modification, or deletion.

For more in-depth information on the vulnerability and specific attack scenarios, please refer to the original security advisory: Node.js Security Advisory - CVE-2023-32004

Exploit Details

To exploit this vulnerability, an attacker could craft a malicious buffer object and use it as a file path argument in a vulnerable Node.js application. This would allow them to bypass the permission model of the system and perform unauthorized actions. The following example demonstrates a simple method to create a malicious buffer:

const maliciousBuffer = Buffer.from('/etc/passwd');
fs.exists(maliciousBuffer, (err, exists) => {
  if (err) console.error(err);
  else console.log('File exists:', exists);
});

When using this malicious buffer, it's possible to bypass the permission model and gain unauthorized access to sensitive files.

Mitigation Steps

As of the time of writing, there is no official patch for this vulnerability in Node.js 20. Users are advised to consider the following steps to mitigate the risks:

Refrain from using the experimental permission model in production environments.

2. Update your Node.js application to use a more stable permission model or use third-party permission libraries that are not affected by this vulnerability.

Monitor for any official updates and patches from the Node.js team.

For updates and more information on this vulnerability and future patches, please visit the official Node.js Security page: Node.js Security

In conclusion, the CVE-2023-32004 is a vulnerability affecting the experimental permission model in Node.js version 20, and all users utilizing this model are at risk. Please follow the mitigation steps outlined and keep an eye on official updates from the Node.js team to ensure the security of your Node.js-based applications.

Timeline

Published on: 08/15/2023 16:15:00 UTC
Last modified on: 08/22/2023 14:13:00 UTC