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

Autodesk Maya Script Nodes Arbitrary Command Execution



1. *Advisory Information*

Title: Autodesk Maya Script Nodes Arbitrary Command Execution
Advisory Id: CORE-2009-0910
Advisory URL:
http://www.coresecurity.com/content/maya-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: 36636
CVE Name: CVE-2009-3578



3. *Vulnerability Description*

Autodesk Maya [2] is a high-end 3D computer graphics and 3D modeling
software package.

Autodesk Maya offers so called "Script Nodes" as a way to program
animation behavior using MEL (Maya Embedded Language) and the Python
programming language. The Autodesk Maya file formats support embedding
of scripting code as part of a scene package. Programs embeded in Maya
files using scripting code are automatically executed upon opening of
the file. An attacker can take control of a system where Maya is
installed by sending a specially crafted scene package and enticing
the user to open it. The scripting code will run with the privileges
of the user running the Maya application.


4. *Vulnerable packages*

   . Autodesk Maya 2010
   . Autodesk Maya 2009
   . Autodesk Maya 2008
   . Autodesk Maya 8.5
   . Autodesk Maya 8.0
   . Alias Wavefront Maya 7.0
   . Alias Wavefront Maya 6.5


5. *Vendor Information, Solutions and Workarounds*

The vendor did not provide fixes or workaround information.

You can prevent script nodes from executing when you open a file by
following these steps:

   . Select File > Open Scene > .
   . Turn off Execute Script Nodes.
   . Click Open.


6. *Credits*

This vulnerability was discovered and researched by Diego Juarez 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 Maya offers so called "Script Nodes" as a way to program
animation behavior using MEL (the proprietary Maya scripting language)
and the Python programming language. Script nodes are saved on the
'.mb' and '.ma' file formats along with geometry and the rest of the
scene data. By using files with embedded scripting code it is possible
to execute arbitrary commands without any restriction and without
requiring any user interaction after a user opened a malicious scene
file.

The following steps work as Proof of Concept:


   . Open Maya.
   . Add some geometry.
   . Go to Window/Animation Editors/Expression Editor.
   . Put a name on it, set "Evaluate On" to "Open/Close", insert
python code within quotes like this:



/-----
      
      python("import os");
      python("os.system('%SystemRoot%\\system32\\calc.exe')");  
      
- -----/
 Save scene to a file with '.mb' or '.ma' format. Next time you open
the scene, calc.exe will be run. This same behavior can be obtained
using pure MEL code.


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-2009-0910 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-2009-0910 as "user release".



9. *References*

[1] The author participated in Core Bugweek 2009 as member of the team
"Gimbal Lock N Load".
[2]
http://usa.autodesk.com/adsk/servlet/pc/index?siteID=123112&id=13577897 


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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