CVE CyberSecurity Database News

CVE-2023-5476: Analyzing and Exploiting Use after Free Vulnerability in Google Chrome's Blink History

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This in-depth analysis and exploitation of the CVE-2023-5476 vulnerability cover important aspects from the initial discovery to the final exploit of the bug. We start with an overview of the vulnerability's impact and then dive into the technical details of how it works, along with code snippets. It is important to understand that exploiting this vulnerability could lead to potential heap corruption, which makes it a significant threat. This post also contains links to original references for further understanding.

Overview

The CVE-2023-5476 vulnerability affects Google Chrome version ranging prior to 118..5993.70. It is a Use after Free vulnerability in the Blink history of Google Chrome, which, if exploited, could allow a remote attacker to potentially cause heap corruption via a crafted HTML page. Chromium security rates this vulnerability as "Medium" severity.

Technical Details

A Use after Free vulnerability is a common memory-related bug that occurs when a program continues to use a pointer even after it has released the associated memory allocation. The memory can then be reallocated to another data structure or object, which leads to various possible outcomes, such as the original data being overwritten, or control flow hijacking by an attacker.

The vulnerability in question resides in the Blink history component of Google Chrome, which manages browsing history and navigation actions, parsing input from users, and tracking visited sites.

Exploit Details

An attacker could create a specially crafted HTML page that uses JavaScript to manipulate the browsing history by triggering the vulnerable code in the Blink History API. Here is an example of a vulnerable code snippet:

<html>
<head>
  ...
</head>
<body>
  ...
  <script>
    function triggerVulnerability() {
      window.history.go(-1);
      // vulnerable code here...
    }
  </script>
</body>
</html>

As you can see, the JavaScript code calls window.history.go(-1);, which, when executed, moves the user back one step in the browser history. The memory associated with this action could be released, but if the code continues to reference the memory location for subsequent operations, it could lead to the Use after Free vulnerability.

To exploit this bug successfully, an attacker could create a malicious HTML page and send it to the target user utilizing techniques such as phishing emails, social engineering, or compromising a legitimate website. Once the target user navigates to the malicious page, the vulnerability is triggered, potentially allowing the attacker to execute arbitrary code or cause a denial of service by crashing the browser.

- Chromium Bug Tracker: https://bugs.chromium.org/p/chromium/issues/detail?id=728594
- CVE Mitre: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-5476
- National Vulnerability Database (NVD): https://nvd.nist.gov/vuln/detail/CVE-2023-5476
- Chrome Releases Blog: https://chromereleases.googleblog.com/2023/04/stable-channel-update-for-desktop_12.html

Conclusion

In conclusion, the CVE-2023-5476 vulnerability represents a significant risk, given its potential for causing heap corruption via remote code execution. Users are highly recommended to update their Google Chrome browser to the patched version (118..5993.70 or later) to protect against potential exploitation. It is also essential to be aware of potential phishing attempts and maintain secure web browsing habits to minimize the risk of falling victim to such vulnerabilities.

Timeline

Published on: 10/11/2023 23:15:10 UTC
Last modified on: 10/20/2023 20:19:10 UTC