Windows C++ / Hook Injection

Code

#include <windows.h>

// The function to be injected as a hook
LRESULT CALLBACK HookFunction(int code, WPARAM wParam, LPARAM lParam) {
  // Perform malicious actions here
  
  // Return the result of the next hook in the chain
  return CallNextHookEx(NULL, code, wParam, lParam);
}

int main() {
  // Install the hook
  HHOOK hHook = SetWindowsHookEx(WH_MOUSE_LL, HookFunction, NULL, 0);
  
  // Run the message loop to receive events
  MSG msg;
  while (GetMessage(&msg, NULL, 0, 0)) {
    TranslateMessage(&msg);
    DispatchMessage(&msg);
  }
  
  // Uninstall the hook
  UnhookWindowsHookEx(hHook);
  
  return 0;
}