XnView 2.03 - '.pct' Buffer Overflow

Core Security - Corelabs Advisory

http://corelabs.coresecurity.com/



XnView Buffer Overflow Vulnerability





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*



Class: Buffer overflow [CWE-119]

Impact: Code execution

Remotely Exploitable: Yes

Locally Exploitable: No

CVE Name: CVE-2013-2577





3. *Vulnerability Description*



XnView [1], [2] 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.





6. *Credits*



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

'CORE-2013-0705-xnview-poc-4895a357a242d3c78.PCT'[3]:



/-----

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.





9. *References*



[1] http://www.xnview.com/.

[2] http://www.xnview.com/en/xnview/.

[3]

http://www.coresecurity.com/system/files/attachments/2013/07/CORE-2013-0705-xnview-poc-4895a357a242d3c78.zip

https://github.com/offensive-security/exploit-database-bin-sploits/raw/master/sploits/27049.zip



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11. *About Core Security Technologies*



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12. *Disclaimer*



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.