[Full-disclosure] Re: Snort BackOrifice Fun

From: Krpata, Tyler (tkrpata_at_bjs.com)
Date: 10/21/05

  • Next message: Frank Knobbe: "Re: [Full-disclosure] Question"
    Date: Fri, 21 Oct 2005 17:22:03 -0400
    To: <full-disclosure@lists.grok.org.uk>

    > Attached some in-progress code for the snort bug, getting through the
    > while() loop that modifies both 'i' and 'len' is annoying. Any ideas
    > making this more reliable? It works great on my -ggdb version , but
    > off a page during a memcmp() on my normal binary.

     The problem is that you reach a point (coincidentally a page before
    eip) where you start to clobber the pointer that is being used to copy
    your user data into memory. Once that happens you're no longer writing
    to the location you want to be writing to.


    Bf??????? [41414141] len
    Bf??????? [41414141] id
    Bf??????? [41414141] l
    Bf??????? [41414141] i
    Bf??????? [41414141] type
    Bf??????? [Bf????41] buf_ptr
    Bf??????? [????????]
    Bf??????? [????????]
    Bf??????? [????????] eip


    Somewhere else...
    Bf????41 [41414141]

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