CVE-2024-4949 - Understanding the Use-After-Free Vulnerability in V8 of Google Chrome supporting versions <125..6422.60

Introduction: A Use-After-Free vulnerability, classified under CVE-2024-4949, has been identified in the V8 engine of Google Chrome browser versions prior to 125..6422.60. In this post, we will delve into the details of this vulnerability, which can potentially be exploited by a remote attacker to cause heap corruption via a specifically crafted HTML page. The Chromium security team has classified the severity of this issue as 'Medium.' Additionally, we will provide code snippets where necessary and links to relevant references, while keeping readability simple and user-friendly.

What is CVE-2024-4949?

CVE-2024-4949 refers to a specific instance of the Use-After-Free vulnerability in the V8 engine within Google Chrome browser versions up to 125..6422.60. This vulnerability enables a remote attacker to potentially exploit heap corruption through a crafted HTML page, which can lead to various undetermined consequences. To better understand the nature of this vulnerability, let us first define the term 'Use-After-Free.'

What is Use-After-Free (UAF)?

UAF refers to a class of memory corruption issues where memory that has been freed is still accessed later in the program. In programming, heap memory is dynamically allocated and deallocated. So, when an object is no longer required, a programmer may use "free()" function to release the memory used by the object. However, if a pointer (reference) to the freed object still exists and is used without ensuring its validity, a UAF vulnerability is triggered.

How is CVE-2024-4949 exploited?

In the context of Google Chrome, an attacker can exploit this UAF vulnerability by creating and distributing a malicious HTML page. When this page is opened in a vulnerable Chrome browser, the attacker may execute arbitrary code and potentially access sensitive information. A code snippet representing the interaction leading to this vulnerability is as follows:

// (Assuming a vulnerability within a C++ API called by V8)
void exampleFunction(ExampleObject *object) {
  object->set_data(new ExpensiveResource());

  // If vulnerability exists, intervening code could trigger
  // destruction of the object.
  
  // Using the object after it has been freed can lead to heap corruption
  object->call_function();
}

Crafting an HTML page to exploit this vulnerability would involve creating an object and causing the call_function() to execute after the object has been freed.

How has the vulnerability been addressed?

Google Chrome has released an update (version 125..6422.60) which addresses and resolves the CVE-2024-4949 vulnerability. Users are encouraged to ensure that their Google Chrome browser is updated to the latest version to avoid any potential exploitation of the vulnerability.

References

- Original Advisory: Google Chrome Releases
- Analysis: Chromium Issue Tracker
- CVE Details: National Vulnerability Database

Conclusion

In this post, we have provided a simple, user-friendly, and exclusive overview of the CVE-2024-4949 Use-After-Free vulnerability affecting Google Chrome browser versions prior to 125..6422.60. We have explored UAF's definition, how it can be exploited in Google Chrome, and the steps to mitigate its impact by updating the browser to the latest version. By understanding the implications of the CVE-2024-4949 vulnerability and ensuring that our browsers are up-to-date, we can better protect ourselves from potential security risks.

Timeline

Published on: 05/15/2024 21:15:09 UTC
Last modified on: 07/03/2024 02:08:21 UTC