CVE-2024-21538: Regular Expression Denial of Service (ReDoS) Vulnerability in cross-spawn until version 7..4

Cross-spawn is a popular Node.js package used for spawning child processes in a cross-platform manner. It comes as a dependency in many projects, and therefore its security is of utmost concern. In this post, we will discuss a recently reported Regular Expression Denial of Service (ReDoS) vulnerability, assigned as CVE-2024-21538, which affects versions of cross-spawn before 7..5.

Affected Versions

Versions of the cross-spawn package before 7..5 are vulnerable to ReDoS.

The vulnerability

The ReDoS vulnerability arises from improper input sanitization. An attacker can craft a very large and well-crafted string that can lead to a significant increase in CPU usage and potentially crash the program. This can be achieved due to a problematic regular expression in the package's codebase.

Code snippet illustrating the issue

const crossSpawn = require('cross-spawn');

const malicious_string = "very_large_and_crafted_string_here";

crossSpawn.sync('some_command', [malicious_string]);

In this code snippet, the crossSpawn.sync() function is called with a malicious string. Due to improper input sanitization, this string can trigger the regular expression to consume too much time and resources, causing CPU usage to spike and potentially crashing the program.

Original References

1. The official CVE information can be found at: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-21538

2. The original issue report in the cross-spawn repository can be found at: https://github.com/moxystudio/node-cross-spawn/issues/issuenumber (replace 'issuenumber' with the actual issue number if available)

The exploit details

As explained earlier, an attacker can exploit the vulnerability by crafting a malicious string that triggers the problematic regular expression. The following is an example of such a string:

aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa!

This string consists of 64 characters followed by an exclamation mark. When passed to the vulnerable crossSpawn.sync() function, it triggers the ReDoS vulnerability.

Mitigation and Solution

Updating cross-spawn to version 7..5 or later, where the vulnerability has been fixed, is the only known solution at this time. It is highly recommended to do so to avoid potential attacks exploiting this vulnerability.

"cross-spawn": "^7..5"

}

Conclusion

Ensuring the security of dependencies within your projects is crucial for safeguarding your applications and user information. By staying up to date with the latest versions of dependencies and addressing discovered vulnerabilities, you can maintain a secure environment and protect against potential attacks.
In the case of CVE-2024-21538, make sure you update cross-spawn to version 7..5 or later to protect your application from this ReDoS vulnerability.

Timeline

Published on: 11/08/2024 05:15:06 UTC
Last modified on: 11/19/2024 14:15:17 UTC