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RE: Unchecked buffer in mstask.dll



On Thu, 15 Jul 2004, Paul Szabo wrote:

> Being curious, on Win2k, I copied cmd.exe (from winnt\system32) as xyz.pif;
> then (right-click) Properties, Program crashes explorer. Is this related to
> IconHandler, and is it exploitable?

        Right -- in Win2K SP4 clicking on [Program] tab of Properties
window causes "access violation" -- the memory at 0x00000000 could not be
"read" by SHELL32.DLL.  MSVC++, acting as a debugger, shows a mixture of
KERNEL32, COMCTL32, USER32, SHELL32 and SHLWAPI in stack trace.

        Disassembly window shows that there was an attempt to read dword
at [EAX] (EAX=0).  So at first glance this doesn't seem to be trivially
exploitable, but I'm not a win32 expert, and intuition suggests that there
must be a way.

        _________________________________________
          Dmitry Yu. Bolkhovityanov
          The Budker Institute of Nuclear Physics
          Novosibirsk, Russia