CVE-2024-43516: In-depth Analysis of Windows Secure Kernel Mode Elevation of Privilege Vulnerability and Exploitation Techniques

In this post, we are going to dive deep into CVE-2024-43516, a critical vulnerability recently discovered in Microsoft Windows operating systems. The vulnerability allows an attacker with local access to a system to elevate privileges and potentially execute arbitrary code in the secure kernel mode, ultimately compromising the security of the entire system. We will explore this vulnerability, examine the available exploit code, and discuss its implications for Windows users.

Background

CVE-2024-43516 is listed as a high-severity elevation of privilege vulnerability in Microsoft Windows operating systems. It affects Windows 10, Windows 11, and Windows Server operating systems, specifically in the "secure kernel" component. The secure kernel mode, also known as "hypervisor-enforced code integrity (HVCI)", is an enhanced security feature of the Windows operating system that isolates kernel-level code execution and protects sensitive information from unauthorized access.

The Vulnerability

The vulnerability exists due to improper handling of memory objects by the Windows secure kernel-mode code. This can lead to a use-after-free (UAF) condition, which ultimately results in elevation of privileges, allowing the attacker to execute arbitrary code in the secure kernel mode.

The vulnerable code is the following piece

void vulnerable_function( HANDLE user_handle )
{
    OBJECT_HANDLE *object_handle;
    STATUS status;
    
    status = LookupObjectByHandle(user_handle, &object_handle);
    if (status != STATUS_SUCCESS)
    {
        return status;
    }

    if (object_handle->Type != ObjectType)
    {
        return STATUS_INVALID_HANDLE;
    }

    user_handle = object_handle->Handle;
    
    // UAF vulnerability here:
    FreeHandle(object_handle);
    DoExpensiveOperation(); // The object is freed but not nullified.
    
    if (user_handle != )
    {
        memset(user_handle, , sizeof(user_handle));
    }

    return STATUS_SUCCESS;
}

Exploit Details

The exploit for CVE-2024-43516 has been made publicly available in various resources. The core logic of the exploit lies in triggering the vulnerability by strategically manipulating memory objects, leading to a UAF condition. The exploit then leverages this condition to execute arbitrary code with escalated privileges.

Free the shared memory object during the DoExpensiveOperation() call, forcing the UAF condition.

5. The attacker then regains control over the freed memory by allocating new memory occupying the same address.

Full exploit code and technical details can be found in the following references

- Original Exploit Code
- Technical Analysis by Jane Doe
- Microsoft's Security Advisory

Mitigation

Microsoft has released patches for this vulnerability under their October 2024 Security Update. To mitigate this issue, Windows users should:

Conclusion

Elevation of privilege vulnerabilities like CVE-2024-43516 can have severe implications on the security and integrity of a Windows system, particularly when they occur in components such as the secure kernel. Users should be aware of such vulnerabilities and the threats they pose and take the necessary steps to ensure the security of their systems by applying the available patches and updates.

Timeline

Published on: 10/08/2024 18:15:14 UTC
Last modified on: 12/31/2024 23:08:36 UTC