Re: BoF in Windows 2000: ddeshare.exe

Valdis.Kletnieks_at_vt.edu
Date: 11/09/04

  • Next message: Sune Kloppenborg Jeppesen: "[ GLSA 200411-16 ] zip: Path name buffer overflow"
    To: Jack C <jack@crepinc.com>
    Date: Tue, 09 Nov 2004 14:59:20 -0500
    
    
    

    On Mon, 08 Nov 2004 21:24:00 EST, Jack C said:

    > Run in OllyDbg, we find that the above string makes the program attempt
    > to JMP to 0x00420042. It just so happens that Hex 42 is a "B". So the
    > two B's at the end of the exploit string change the instrucation pointer.
    >
    > As far as I can tell, this is not exploitable to run a shellcode because
    > of the fact that NULL's are inserted between charactors.

    Ah, but what if the 2 trailing B's are replaced by 2 Unicode chars that
    together take up 4 bytes? ;)

    > But besides
    > that, it would only give the same privliges that you already have to run
    > the program in the first place. It simply points out bad coding.

    If you can find a way to programmaticaly call the same code, this can be
    leveraged by a trojan code. Consider: If there was a way to get a user to
    click on a URL that resolved to a file share and fall into this code, this
    could be used as an initial attack point for a worm.....

    
    



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