Re: looking for recursion stack overflow exploit

From: Valdis.Kletnieksat_private
Date: Fri Nov 22 2002 - 06:34:49 PST

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    On Wed, 20 Nov 2002 07:27:21 EST, bukysat_private said:
    > While a recursion-induced stack overflow can obviously lead to a
    > denial-of-service attack, are there any examples of it being turned
    > into an opportunity for remote execution?
    
    The only possibility I can see here is if you can find some way to subvert
    the "stack size exceeded" error handler when the recursion finally runs out
    of stack.  However, it's probably not productive, since most programs don't
    include recursive code to start with, and if you are able to subvert an error
    handler, it's a lot faster/easier to hijack whatever your system's moral
    equivalent of the Unix SIGSEGV, and then reference non-existent memory and
    exploit quickly.
    
    On the other hand, the Unix libc usually contains the qsort() and ftw()
    routines, which might be interesting.  ftw() is prone to race conditions,
    and it *might* be possible to feed qsort() a specially crafted array of
    values that would give it indigestion at an inconvenient time (the place
    to start would probably be an out-of-memory condition in the compare() function
    passed to qsort()).
    -- 
    				Valdis Kletnieks
    				Computer Systems Senior Engineer
    				Virginia Tech
    
    
    
    



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