CVE-2024-43566 is a newly identified remote code execution (RCE) vulnerability affecting Microsoft's Chromium-based Edge browser. Remote code execution vulnerabilities are a serious concern, as they allow attackers to take control of a victim's device remotely. In the case of CVE-2024-43566, the vulnerability exists due to improper handling of JavaScript code during the rendering of specific websites. This blog post will cover the details of this vulnerability, including an analysis of a code snippet, links to official references and resources, and information about potential exploits.

Vulnerability Overview

CVE-2024-43566 is a Microsoft Edge (Chromium-based) vulnerability that results from improper handling of JavaScript code. If a user navigates to a maliciously crafted website, the site could run arbitrary code on the user's device. This can lead to complete system compromise for any affected user. Due to the severity of RCE vulnerabilities, Microsoft has deemed CVE-2024-43566 a high priority and released a patch addressing this issue.

Below is an example of the vulnerable code within Microsoft Edge

function vulnerableFunction(data) {
  const newObj = JSON.parse(data);
  return newObj.property;
}

window.addEventListener('message', (event) => {
  if (event.origin === 'https://trusted.website.com';) {
    const result = vulnerableFunction(event.data);
    // ...
  }
});

In this example, the vulnerableFunction function takes a user-supplied input (from the 'message') and parses it using JSON.parse(). After parsing, the function retrieves the 'property' attribute of the object and assigns it to the variable newObj. An attacker could craft a malicious JSON object to exploit this vulnerability.

Original References

The official CVE entry and additional resources for CVE-2024-43566 can be found at the following links:

1. CVE-2024-43566 - NIST NVD
2. Microsoft Security Update Guide - CVE-2024-43566
3. Microsoft Edge - Release Notes

Exploit Details

To exploit CVE-2024-43566, an attacker would first need to craft a malicious website containing JavaScript code designed to take advantage of the vulnerability. For example, the attacker might create the following malicious payload:

const maliciousPayload = `{
  "property": {
    "constructor": {
      "prototype": {
        "toString": function() {
          // Insert malicious code here
        }
      }
    }
  }
}`;

window.parent.postMessage(maliciousPayload, 'https://trusted.website.com';);

In this example, the attacker creates a JSON object (maliciousPayload) with a specially crafted 'property' attribute. The 'toString' function is hijacked to execute the attacker's code when the newObj assignment is made in the vulnerable application

Once the website is created, the attacker would need to convince a user to visit the site or click on a malicious link while using a vulnerable version of Microsoft Edge. Upon visiting the malicious site, the specially crafted JavaScript code would execute arbitrary code on the user's device.

Mitigations

Microsoft has patched the vulnerability in their security update, and it is crucial for users to update their Microsoft Edge browser to the latest version as soon as possible. Users should also avoid visiting suspicious websites and clicking on unexpected links, as these can lead to exploitation and further harm.

Conclusion

CVE-2024-43566 highlights the importance of maintaining up-to-date software and staying vigilant online. By understanding the implications of this vulnerability and applying the provided patches, users can protect their devices and maintain secure browsing practices.

Timeline

Published on: 10/17/2024 23:15:14 UTC
Last modified on: 11/12/2024 17:21:57 UTC