buuctf-findKey

exe文件

运行发现这个窗口,没有任何消息

32位

进入字符串就发现了flag{

左边红色代表没有F5成功

我们再编译一下(选中红色的全部按p)

LRESULT __stdcall sub_401640(HWND hWndParent, UINT Msg, WPARAM wParam, LPARAM lParam)
{
  int v5; // eax
  size_t v6; // eax
  DWORD v7; // eax
  int v8; // eax
  int v9; // eax
  int v10; // [esp+4Ch] [ebp-400h]
  UINT v11; // [esp+50h] [ebp-3FCh]
  CHAR v12[256]; // [esp+54h] [ebp-3F8h] BYREF
  char v13[7]; // [esp+154h] [ebp-2F8h] BYREF
  __int16 v14; // [esp+15Bh] [ebp-2F1h]
  char v15; // [esp+15Dh] [ebp-2EFh]
  char Str[253]; // [esp+160h] [ebp-2ECh] BYREF
  __int16 v17; // [esp+25Dh] [ebp-1EFh]
  char v18; // [esp+25Fh] [ebp-1EDh]
  CHAR v19[256]; // [esp+260h] [ebp-1ECh] BYREF
  CHAR String[4]; // [esp+360h] [ebp-ECh] BYREF
  int v21; // [esp+364h] [ebp-E8h]
  __int16 v22; // [esp+368h] [ebp-E4h]
  CHAR Text[32]; // [esp+36Ch] [ebp-E0h] BYREF
  struct tagRECT Rect; // [esp+38Ch] [ebp-C0h] BYREF
  CHAR Buffer[100]; // [esp+39Ch] [ebp-B0h] BYREF
  HDC hdc; // [esp+400h] [ebp-4Ch]
  struct tagPAINTSTRUCT Paint; // [esp+404h] [ebp-48h] BYREF
  int v28; // [esp+444h] [ebp-8h]
  int v29; // [esp+448h] [ebp-4h]
 
  LoadStringA(hInstance, 0x6Au, Buffer, 100);
  v11 = Msg;
  if ( Msg > 0x111 )
  {
    if ( v11 == 517 )
    {
      if ( strlen((const char *)String1) > 6 )
        ExitProcess(0);
      if ( strlen((const char *)String1) )
      {
        memset(v19, 0, sizeof(v19));
        v6 = strlen((const char *)String1);
        memcpy(v19, String1, v6);
        v7 = strlen((const char *)String1);
        sub_40101E(String1, v7, (LPSTR)String1);
        strcpy(Str, "0kk`d1a`55k222k2a776jbfgd`06cjjb");
        memset(&Str[33], 0, 0xDCu);
        v17 = 0;
        v18 = 0;
        strcpy(v13, "SS");
        *(_DWORD *)&v13[3] = 0;
        v14 = 0;
        v15 = 0;
        v8 = strlen(Str);
        sub_401005(v13, (int)Str, v8);
        if ( _strcmpi((const char *)String1, Str) )
        {
          SetWindowTextA(hWndParent, "flag{}");
          MessageBoxA(hWndParent, "Are you kidding me?", "^_^", 0);
          ExitProcess(0);
        }
        memcpy(v12, &unk_423030, 0x32u);
        v9 = strlen(v12);
        sub_401005(v19, (int)v12, v9);
        MessageBoxA(hWndParent, v12, 0, 0x32u);
      }
      ++dword_428D54;
    }
    else
    {
      if ( v11 != 520 )
        return DefWindowProcA(hWndParent, Msg, wParam, lParam);
      if ( dword_428D54 == 16 )
      {
        strcpy(String, "ctf");
        v21 = 0;
        v22 = 0;
        SetWindowTextA(hWndParent, String);
        strcpy(Text, "Are you kidding me?");
        MessageBoxA(hWndParent, Text, Buffer, 0);
      }
      ++dword_428D54;
    }
  }
  else
  {
    switch ( v11 )
    {
      case 0x111u:
        v29 = (unsigned __int16)wParam;
        v28 = HIWORD(wParam);
        v10 = (unsigned __int16)wParam;
        if ( (unsigned __int16)wParam == 104 )
        {
          DialogBoxParamA(hInstance, (LPCSTR)0x67, hWndParent, (DLGPROC)DialogFunc, 0);
        }
        else
        {
          if ( v10 != 105 )
            return DefWindowProcA(hWndParent, Msg, wParam, lParam);
          DestroyWindow(hWndParent);
        }
        break;
      case 2u:
        PostQuitMessage(0);
        break;
      case 0xFu:
        hdc = BeginPaint(hWndParent, &Paint);
        GetClientRect(hWndParent, &Rect);
        v5 = strlen(Buffer);
        DrawTextA(hdc, Buffer, v5, &Rect, 1u);
        EndPaint(hWndParent, &Paint);
        break;
      default:
        return DefWindowProcA(hWndParent, Msg, wParam, lParam);
    }
  }
  return 0;
}

win32逆向的关键就是 messagebox 这个函数

弹窗

这两个都是输出kid

我们看中间那个

慢慢跟进就ok了

很简单了逻辑

flag{n0_Zu0_n0_die}