^{CVE-2021-44906:}Prototype Pollution vulnerability in Minimist package versions 1.2.5 and earlier allows attackers to modify JavaScript object prototype properties.

Overview

Minimist is a widely used npm package for parsing command-line arguments in Node.js applications. The vulnerability (CWE-1321: Improperly Controlled Modification of Object Prototype Attributes) allows attackers to modify JavaScript's Object prototype through specially crafted input. The issue occurs in the setKey() function which handles nested properties but doesn't properly check for properties like "proto" that could modify the Object prototype. When exploited, this vulnerability can lead to serious security issues including application crashes, unexpected behavior, authentication bypasses, or even remote code execution depending on how the affected application uses object properties. The vulnerability affects all versions of Minimist up to and including 1.2.5.

Remediation

To remediate this vulnerability, take the following actions:

1. Update the Minimist package to version 1.2.6 or later, which contains the fix for this vulnerability.
2. If direct updating is not immediately possible, implement input validation to prevent "proto" and other dangerous properties from being used in command-line arguments.
3. Consider using Object.create(null) to create objects without prototype when handling untrusted input.
4. Implement Object.freeze(Object.prototype) in your application to prevent modifications to the Object prototype, though this may affect functionality in some cases.
5. Run dependency scanning tools regularly to identify vulnerable dependencies in your applications.
6. Monitor your applications for unexpected behavior that might indicate exploitation of this vulnerability.

References

1. GitHub issue describing the vulnerability: https://github.com/substack/minimist/issues/164
2. Snyk vulnerability report: https://snyk.io/vuln/SNYK-JS-MINIMIST-559764
3. Proof of Concept exploit: https://github.com/Marynk/JavaScript-vulnerability-detection/blob/main/minimist%20PoC.zip
4. Vulnerable code reference: https://github.com/substack/minimist/blob/master/index.js#L69
5. NetApp security advisory: https://security.netapp.com/advisory/ntap-20240621-0006/
6. Stack Overflow discussion on JavaScript prototype properties: https://stackoverflow.com/questions/8588563/adding-custom-properties-to-a-function/20278068#20278068