Vulnerability Development: Re: problem to exploit a stack overflow

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In-Reply-To: <433ee3d9050524070923ba6ab5 () mail gmail com>

> so the access violation happend (this time)  in the beging of the
> shellcode !!!? is that a security future in xp sp2 ? or samething
> else? can sameone help me to understand this .
> thank you
You have overwritten ebp with nops... then you are trying to mov the value 63h to ebp-4 and you get an access violation.

Basically what you are trying to do with your shellcode is call winexec routine on "cmd" - and for that you are trying 
to push "cmd" onto the stack, then push a null, then call winexec.

Unfortunately for you, ebp is not pointing to the stack - you have corrupted it with nops, but since you got control of 
the cpu - you can move whatever value to whatever (accessible) location and fix things...
Also, you can reset all the registers to whatever values you want.

Good luck