Re: BoF in Windows 2000: ddeshare.exe

[Valdis.Kletnieks () vt edu]

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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