The CVE-2024-42330 concerns a vulnerability in the HttpRequest object, specifically in the handling of HTTP headers in server responses. The HttpRequest object is commonly used to send and receive data between web applications and servers. While handling HTTP headers, however, the object is not correctly encoding the returned strings, potentially giving attackers access to hidden properties of JavaScript objects.

In this post, we'll explore the details of this vulnerability, demonstrate a code snippet exhibiting the issue, provide links to the original references and discuss potential exploitation methods for this vulnerability.

Vulnerability Details

When sending HTTP requests and receiving server responses, the HttpRequest object is responsible for handling HTTP headers. The vulnerability arises when it's time to process the headers from the server's response. The HttpRequest object is failing to properly encode the strings that represent the headers, leading to the creation of internal strings that could be utilized to access hidden properties within JavaScript objects.

Below is a code snippet demonstrating the vulnerability

let xhr = new XMLHttpRequest();
xhr.onreadystatechange = function() {
    if (xhr.readyState == 4) {
        let serverHeaders = xhr.getAllResponseHeaders();
        let vulnerableHeader = serverHeaders['X-Custom-Header'];
        if (vulnerableHeader) {
            console.log('Vulnerable header value:', vulnerableHeader);
        }
    }
};
xhr.open("GET", "https://example.com/api/v1/data";);
xhr.setRequestHeader("Content-Type", "application/json");
xhr.send();

In this code snippet, we create an XMLHttpRequest and fetch data from a server. Once the server returns a response, we get the headers using xhr.getAllResponseHeaders() method and log the vulnerable header's value to the console.

The issue here is that the returned header values are not properly encoded before being assigned to JavaScript strings. This can lead to attackers having unauthorized access to undocumented and hidden properties within objects.

Original References

1. National Vulnerability Database (NVD) - CVE-2024-42330
2. Vulnerability Details on HttpRequest Object and Exploit Information

Exploiting the Vulnerability

Exploiting the CVE-2024-42330 vulnerability requires attackers to find a site using the HttpRequest object with vulnerable code. Considering that JavaScript runs on the client-side, a carefully crafted script could be executed in a user's browser to take advantage of this vulnerability.

A potential exploit scenario would involve the attacker sending a specifically formatted HTTP header response containing forbidden characters that, when parsed by the vulnerable code, could give access to hidden object properties. This, in turn, could lead to arbitrary code execution, data exfiltration, or other damaging operations.

Conclusion

The HttpRequest object's vulnerability in processing HTTP headers opens doors for potential attackers to exploit. It's crucial to always correctly encode strings, especially when handling user input or external data. Developers and security teams must actively implement secure coding practices and keep their software up to date to prevent such vulnerabilities from occurring in the future.

Timeline

Published on: 11/27/2024 12:15:21 UTC