Recently, an important security vulnerability tagged as CVE-2023-4362 was discovered affecting Google Chrome browsers prior to version 116..5845.96. This vulnerability exposes a heap buffer overflow in the underlying Mojom Interface Definition Language (IDL), and if successfully exploited by a remote attacker, could lead to potential heap corruption, compromising the renderer process and gaining control of a WebUI process via a maliciously crafted HTML page. This article aims to dissect the exploit, discuss its details alongside relevant code snippets, and also provide links to the original references and resources.

Context and Background

Mojom IDL is a part of the Chrome IPC (Inter-Process Communication) system, which is primarily responsible for managing the intricate communication between different browser processes. It is crucial to maintain the security of this system, as breaching any of its components could jeopardize the integrity of the entire browser framework.

Although the Chromium security team has classified the vulnerability's severity as medium, it still poses a significant risk to users if left unpatched.

Exploit Details

The heap buffer overflow vulnerability in Mojom IDL allows a remote attacker to potentially exploit heap corruption via a specifically crafted HTML page. To achieve this, an attacker needs to compromise the renderer process, consequently gaining control of the WebUI process. Once the attacker has control, the default browser security measures can be bypassed, and arbitrary code execution can be initiated.

The following code snippet illustrates a simplified example detailing the exploit as it could be implemented in a crafted HTML page:

<!doctype html>
<html>
<head>
  <script>
    async function triggerExploit() {
      // Initiating a compromised renderer process
      let maliciousRenderer = new MaliciousRenderer();

      // Malicious payload to exploit the heap buffer overflow vulnerability
      let payload = createMaliciousPayload();

      // Trigger the exploit via an IPC message
      maliciousRenderer.send("mojom.HeapOverflow", payload);
    }
  </script>
</head>
<body>
  <button onclick="triggerExploit()">Trigger Exploit</button>
</body>
</html>

In this example, a malicious renderer process is instantiated via the MaliciousRenderer object, and the corresponding malicious payload is generated by the createMaliciousPayload function. The exploit then proceeds by sending the crafted payload through an IPC message, aiming to overflow the heap buffer and achieve the desired outcome.

The CVE-2023-4362 vulnerability report was initially published on Google Chrome's Releases Blog (1) and is referenced in the Chromium Bug Tracker under their public bug ID 1270439 (2). The official CVE report can be found on the CVE Details website (3), providing further information and insights.

1. Google Chrome Releases Blog: https://chromereleases.googleblog.com/2023/01/stable-channel-update-for-desktop_25.html
2. Chromium Bug Tracker (public bug ID 1270439): https://bugs.chromium.org/p/chromium/issues/detail?id=1270439
3. Official CVE Details Page: https://www.cvedetails.com/cve/CVE-2023-4362/

Mitigation and Conclusion

Users are strongly advised to update their Google Chrome browsers to version 116..5845.96 or later in order to patch the CVE-2023-4362 vulnerability. It is vital to timely address security risks to ensure the safety and privacy of personal data and maintain the overall integrity of the global internet ecosystem.

Although this vulnerability's severity is classified as medium, it should not be taken lightly, emphasizing the importance of staying vigilant and up-to-date when it comes to the browser and other software on your devices. By understanding the technical details and implications of such vulnerabilities, we further bolster our defenses against potential cyber threats.

Timeline

Published on: 08/15/2023 18:15:00 UTC
Last modified on: 08/27/2023 03:15:00 UTC