1. Advisory Information
Title: XnView Buffer Overflow Vulnerability
Advisory ID: CORE-2013-0705
Advisory URL: http://www.coresecurity.com/advisories/xnview-buffer-overflow-vulnerability
Date published: 2013-07-22
Date of last update: 2013-07-22
Vendors contacted: XnView
Release mode: Coordinated release
2. Vulnerability Information
3. Vulnerability Description
XnView ,  is prone to a security vulnerability when processing PCT files. This vulnerability could be exploited by a remote attacker to execute arbitrary code on the target machine, by enticing the user of XnView to open a specially crafted file.
4. Vulnerable Packages
- XnView v2.03 for Windows.
- Older versions are probably affected too, but they were not checked.
5. Non-Vulnerable Packages
- XnView v2.04.
This vulnerability was discovered and researched by Ricardo Narvaja from Core Exploit Writers Team. The publication of this advisory was coordinated by Fernando Miranda from Core Advisories Team.
7. Technical Description / Proof of Concept Code
Below is shown the result of opening the maliciously crafted file
7C9108F3 8902 MOV DWORD PTR DS:[EDX],EAX 7C9108F5 8941 04 MOV DWORD PTR DS:[ECX+4],EAX 7C9108F8 56 PUSH ESI 7C9108F9 8B75 C8 MOV ESI,DWORD PTR SS:[EBP-38] 7C9108FC 56 PUSH ESI 7C9108FD E8 BAFDFFFF CALL ntdll.7C9106BC << CRASH EAX 00EC3008 ECX 003C95B0 EDX 41424344 EBX 003C0178 ESP 0013E708 EBP 0013E7C4 ESI 00EC3000 EDI 003C0000 EIP 7C9108F3 ntdll.7C9108F3 C 1 ES 0023 32bit 0(FFFFFFFF) P 0 CS 001B 32bit 0(FFFFFFFF) A 1 SS 0023 32bit 0(FFFFFFFF) Z 0 DS 0023 32bit 0(FFFFFFFF) S 1 FS 003B 32bit 7FFDF000(FFF) T 0 GS 0000 NULL D 0 O 0 LastErr ERROR_NO_SCROLLBARS (000005A7) EFL 00010293 (NO,B,NE,BE,S,PO,L,LE) ST0 empty +UNORM 043E 7C910435 0007DC88 ST1 empty +UNORM 0002 0007DB84 00020024 ST2 empty -UNORM DA40 7C901000 7FFDE000 ST3 empty +UNORM 0460 7C90E920 0007DB14 ST4 empty +UNORM 0208 7C913F85 7C913F92 ST5 empty +UNORM 0044 77DDE250 0007DE54 ST6 empty 0.0000000000000006002 ST7 empty 0.0000000000000006002 3 2 1 0 E S P U O Z D I FST 4020 Cond 1 0 0 0 Err 0 0 1 0 0 0 0 0 (EQ) FCW 027F Prec NEAR,53 Mask 1 1 1 1 1 1
As a result, the address 0x41424344 (controlled by the attacker) can be overwritten and the normal execution flow can be altered in order to execute arbitrary code.
003C95B0 32 32 33 34 44 43 42 41 AA AA AA AA 34 35 36 37 2234DCBAªªªª4567 003C95C0 38 90 91 26 32 32 26 3C 36 32 36 36 32 36 3C 3C 8??&22&<626626<< 003C95D0 54 65 6D 73 82 82 87 90 90 99 9A 9B 9E A1 A6 AA Tems?????????¡¦ª 003C95E0 AE AF B3 B5 B5 B6 BB BC BD BD BE BF C1 C3 C7 CB ®¯³µµ¶»¼½½¾¿ÁÃÇË
8. Report Timeline
- 2013-07-04: Core Security Technologies notifies the XnView team of the vulnerability. Publication date is set for July 31st, 2013.
- 2013-07-09: Vendor asks for a report with technical information.
- 2013-07-10: Technical details sent to XnView team.
- 2013-07-11: Vendor notifies that the issue will be fixed in the next product release.
- 2013-07-15: Core asks when the next release has been scheduled.
- 2013-07-16: Vendor notifies that the next product release is scheduled for next week.
- 2013-07-17: Core re-schedules the advisory publication for Monday 22nd.
- 2013-07-22: Advisory CORE-2013-0705 released.
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 enables organizations to get ahead of threats with security test and measurement solutions that continuously identify and demonstrate real-world exposures to their most critical assets. Our customers can gain real visibility into their security standing, real validation of their security controls, and real metrics to more effectively secure their organizations.
Core Security's software solutions build on over a decade of trusted research and leading-edge threat expertise from the company's Security Consulting Services, CoreLabs and Engineering groups. Core Security Technologies can be reached at +1 (617) 399-6980 or on the Web at: http://www.coresecurity.com.
The contents of this advisory are copyright (c) 2013 Core Security Technologies and (c) 2013 CoreLabs, and are licensed under a Creative Commons Attribution Non-Commercial Share-Alike 3.0 (United States) License: http://creativecommons.org/licenses/by-nc-sa/3.0/us/
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.