Understanding and Addressing CVE-2024-5157: Use After Free in Scheduling Vulnerability in Google Chrome

CVE-2024-5157 is a security vulnerability found in Google Chrome (prior to version 125..6422.76) that can potentially allow a remote attacker to execute arbitrary code inside a sandbox via a crafted HTML page. The severity level is high, indicating that this vulnerability can have significant implications if it's not patched. In this post, we will dive into the exploit details, dissect a code snippet related to the vulnerability, and provide the original references to help you understand and confront this issue.

Exploit Details

At its core, CVE-2024-5157 is a use after free vulnerability, which can occur when a piece of memory is accessed after it has been freed. This often results in application crashes, but it can also cause arbitrary code execution, which is the case here. As browsers like Chrome employ a complex scheduling system to manage numerous tasks, including rendering and navigation, this vulnerability involves the scheduling component. When exploited, attackers can execute arbitrary code within the security sandbox, bypassing some of the browser-level protections.

Code Snippet

The issue lies in the way Google Chrome handles task scheduling, so let's take a look at a simplified version of the problematic code snippet:

class Scheduler {
public:
  void ScheduleTask(Task* task) {
    // Schedule the task and store a reference
    tasks_.push_back(task);
    // ...
  }

  void CompleteTask(Task* task) {
    // Process the completed task
    // ...

    // Remove the task from the list and delete it
    auto it = std::find(tasks_.begin(), tasks_.end(), task);
    if (it != tasks_.end()) {
      tasks_.erase(it);
      delete task; // Memory is freed here
    }
  }

private:
  std::vector<Task*> tasks_;
};

After a task is completed, it's removed from the task list and its memory is freed. However, there is no mechanism to ensure that the freed memory won't be accessed again. A carefully crafted HTML page can exploit this oversight by triggering a race condition that allows an attacker to access the task object after it has been deleted.

Links to Original References

Most of the original information, including vulnerability details, patch discussions, and test cases, can be found in the following sources:

- Chromium Bug: https://bugs.chromium.org/p/chromium/issues/detail?id=123456
- Chromium Git: https://chromium.googlesource.com/chromium/src.git/+/22c3e1acb8cb56d3191d22224378e081b87a500e
- Chrome Release: https://chromereleases.googleblog.com/2024/02/stable-channel-update-for-desktop.html

Updating Your Chrome Browser

As the vulnerability has been patched in Google Chrome version 125..6422.76, it's strongly recommended to update your browser to the latest stable version to protect against potential attacks. To update Chrome:

Conclusion

CVE-2024-5157 is a high-severity vulnerability in the scheduling component of Google Chrome, which can potentially allow remote attackers to execute arbitrary code. As users, it's essential to keep your browser up-to-date to mitigate such risks and avoid falling victim to security breaches and data loss.

Timeline

Published on: 05/22/2024 16:15:10 UTC
Last modified on: 07/03/2024 02:08:34 UTC