CVE-2022-3661: A Deep Dive into the Insufficient Data Validation Vulnerability in Google Chrome Extensions and How to Address It

CVE-2022-3661 is a vulnerability detected in Google Chrome versions prior to 107..5304.62, which highlights insufficient data validation in Chrome Extensions. This vulnerability allows a remote attacker, who has already compromised the renderer process, to leak cross-origin data through a malicious Chrome Extension. In this long-read post, we'll go in-depth into the details of this vulnerability, review the relevant code, and discuss potential ways to mitigate and protect against it.

CVE Details

Common Vulnerabilities and Exposures (CVE) Identifier: CVE-2022-3661
Severity: Low (according to Chromium's security severity scale)
Affected Component: Extensions in Google Chrome
Affected Versions: Prior to 107..5304.62

Overview

In Google Chrome, extensions are small software programs that enable users to customize their browsing experience. However, due to insufficient data validation within the extensions component in versions prior to 107..5304.62, an attacker who has already compromised the renderer process can create a custom Chrome Extension with malicious code.

By exploiting this vulnerability, the attacker can access sensitive cross-origin data through their crafted extension, leading to an information leak and potential privacy concerns.

Understanding the Vulnerability

To better grasp the nature of this vulnerability, let’s first understand how Chrome Extensions work.

Chrome Extensions are built using a combination of JavaScript, HTML, and CSS code, which interact with web pages and other extensions using a set of APIs specifically designed for this purpose. These APIs are part of the "chrome" JavaScript namespace and allow extension developers to access and modify various aspects of the web browser, such as tabs, bookmarks, and history.

One essential aspect of Chrome Extensions is their ability to work with cross-origin requests. A cross-origin request is a request for data from a different domain, protocol, or port than the one the browser is currently connected to. By default, web pages and normal JavaScript code are restricted from sending cross-origin requests due to the same-origin policy, which is a security feature implemented in web browsers.

However, Chrome Extensions are an exception to this rule and can request cross-origin data via their background script or content script, provided that the extension developer has declared the appropriate permissions in their extension's manifest file.

This is where the CVE-2022-3661 vulnerability comes into play. A remote attacker, having compromised the renderer process, can create a malicious Chrome Extension that exploits the insufficient data validation in Chrome's extensions component, and subsequently leaks sensitive cross-origin data.

Code Snippet

To illustrate the vulnerability, let's look at a sample Chrome Extension that demonstrates how the malicious code could look like:

// background.js
chrome.runtime.onMessage.addListener((request, sender, sendResponse) => {
  if (request.type === 'leakData') {
    // Make a cross-origin request to example.com
    fetch('https://example.com/data.json';)
      .then(response => response.text())
      .then(data => {
        // Send the data back to the content script
        sendResponse({ success: true, data });
      })
      .catch(error => {
        sendResponse({ success: false, error });
      });

    return true;
  }
});

// content.js
chrome.runtime.sendMessage({ type: 'leakData' }, response => {
  if (response.success) {
    // Do something with the leaked data
    console.log('Leaked data:', response.data);
  } else {
    console.error('Failed to leak data:', response.error);
  }
});

In the code snippet above, the background script (background.js) listens for messages from the content script (content.js) and makes a cross-origin request to "https://example.com/data.json" to obtain the sensitive data. Once the fetch request is complete, the background script sends the data back to the content script, allowing it to be potentially misused by an attacker.

References

For more information on the vulnerability and the affected Chrome versions, kindly refer to the following resources:

1. Chromium Security Advisories
2. CVE-2022-3661 - NVD Detail

Mitigation and Protection

To protect against this vulnerability, users should ensure they are running the latest version of Google Chrome (107..5304.62 or later) as it contains a patch for this issue. Updating the browser to the latest version can be done through the Google Chrome settings menu. Additionally, users are advised to only install trusted Chrome Extensions from verified sources, such as the official Chrome Web Store, and to review the permissions granted to extensions.

Conclusion

Although CVE-2022-3661 is considered a low-severity vulnerability, as it requires the renderer process to be already compromised, it nonetheless underscores the importance of proper data validation and security practices in software development. By understanding potential vulnerabilities and staying up-to-date with updates and patches, users can mitigate risks and protect their sensitive data from being compromised.

Timeline

Published on: 11/01/2022 23:15:00 UTC
Last modified on: 12/08/2022 21:57:00 UTC