Recently, a new Windows Kernel Elevation of Privilege vulnerability has been discovered and is recognized by CVE-2023-21675. This vulnerability allows attackers to exploit the Windows Kernel, which could lead to increased privileges and unauthorized access to various system resources. This specific CVE is unique from other related CVEs, including CVE-2023-21747, CVE-2023-21748, CVE-2023-21749, CVE-2023-21750, CVE-2023-21754, CVE-2023-21755, CVE-2023-21772, CVE-2023-21773, and CVE-2023-21774. In this post, we will discuss the details of the exploit, share some code snippets, and provide links to the original references.

Vulnerability Explanation

The CVE-2023-21675 vulnerability resides in the Windows Kernel, the core component of the operating system responsible for essential system services like hardware interface, memory management, and process management. This specific vulnerability allows an attacker to elevate their privileges, potentially bypassing security measures, and gaining unauthorized access to sensitive information or system configurations. Essentially, this vulnerability could lead to unauthorized access and control over a target system.

Exploit Details

To exploit this vulnerability, an attacker first needs to have local access to the target system with standard user privileges. Exploitation involves misusing a specific function in the Windows Kernel by passing in carefully crafted arguments, which could trigger a buffer overflow. This, in turn, may corrupt the system's memory, allowing the attacker successfully to elevate their privileges.

Code Snippet

Here's a simple pseudocode snippet that outlines the structure of the potentially exploitable function in the Windows Kernel:

bool vulnerable_function(void* target_buffer, size_t target_buffer_size, void* user_buffer, size_t user_buffer_size) {
    if (user_buffer_size > target_buffer_size) {
        return false; // Incorrect buffer size passed

    memcpy(target_buffer, user_buffer, user_buffer_size); // Buffer overflow vulnerability point
    return true;

In this example, the function copies data from the user-supplied buffer (user_buffer) into the target buffer (target_buffer). However, it fails to validate the provided buffer sizes, making it possible to perform a buffer overflow.

To exploit this vulnerability, an attacker may create a larger user_buffer_size value and supply a malicious payload, as exemplified below:

void exploit() {
    void* target_buffer;
    size_t target_buffer_size;
    void* user_buffer;
    size_t user_buffer_size;

    // Obtain and set up the buffers and buffer sizes:
    prepare_exploit(&target_buffer, &target_buffer_size, &user_buffer, &user_buffer_size);

    // Perform the exploit:
    vulnerable_function(target_buffer, target_buffer_size, user_buffer, user_buffer_size);

Original References and Further Details

- Microsoft's Security Update Guide:
- NIST National Vulnerability Database (NVD):
- Mitre CVE Entry:


CVE-2023-21675 represents a serious security vulnerability in the Windows Kernel, which could lead to escalated privileges and unauthorized access to valuable information or system configurations. It is important to remain aware of such vulnerabilities and ensure that your systems are up-to-date and patched. Always follow best practices for secure coding and system administration to minimize your exposure to these risks.


Published on: 01/10/2023 22:15:00 UTC
Last modified on: 02/06/2023 19:15:00 UTC