Re: QW server hole

From: Chris Evans (chrisat_private)
Date: Tue Apr 07 1998 - 22:30:26 PDT

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    Hi,
    
    I've looked into the recently reported QuakeWorld server hole for
    "exploitability" other than DoS.
    
    It seems the smashed buffer is a static one rather than one on the stack;
    when we use a very large string full of 'A' to fill the buffer with, we
    don't get a crash due to execution at address 0x41414141.
    
    Indeed instead we find we have trashed some structures with pointers in.
    The eventual crash is due to a defererence of 0x10+(0x41414141), in the
    function "Z_CheckHeap()".
    
    The actual structure corrupted is called "mainzone", and the actual buffer
    smashed is called "com_token" and appears to be exactly 1024 bytes long.
    
    If, as you say, an ID Software employee has ignored your reports of this
    bug, then that is _very_ poor.
    
    Cheers
    Chris
    



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