Dell Webcam Software Bundled ActiveX Control CrazyTalk4Native.dll sprintf Remote Buffer Overflow Vulnerability

Dell Webcam Software Bundled ActiveX Control CrazyTalk4Native.dll
sprintf Remote Buffer Overflow Vulnerability

Tested against: Microsoft Windows Vista SP2
Microsoft Windows XP SP3
Microsoft Windows 2003 R2 SP2
Internet Explorer 7/8/9

download url of a test version:
http://search.dell.com/results.aspx?c=us&l=en&s=gen&cat=sup&k=Dell+SX2210+monitor&rpp=12&p=1&subcat=dyd&rf=all&nk=f&sort=K&ira=False&~srd=False&ipsys=False&advsrch=False&~ck=anav

file tested: Dell_SX2210-Monitor_Webcam SW RC1.1_ R230103.exe

This package contains the Dell Webcam Central software
developed by Creative Technologies for Dell.

info:
http://dell-webcam-central.software.informer.com/
http://live-cam-avatar-creator.software.informer.com/
http://www.google.com/search?channel=s&hl=en&biw=1024&bih=581&q=13149882-F480-4F6B-8C6A-0764F75B99ED
http://www.google.com/search?sclient=psy-ab&hl=en&biw=1024&bih=581&source=hp&q=crazytalk4.ocx&btnG=Search
http://www.google.com/search?sclient=psy-ab&hl=en&biw=1024&bih=581&source=hp&q=CrazyTalk4Native.dll&btnG=Search
http://dell-webcam-central.software.informer.com/users/
http://live-cam-avatar-creator.software.informer.com/users/

I think this is a very common ActiveX, probably bundled with Dell Notebooks.

Background:
The mentioned software carries a third party ActiveX Control
with the following settings.

Binary path: C:\Program Files\Common Files\Reallusion\CT Player\crazytalk4.ocx
ProgID: CRAZYTALK4.CrazyTalk4Ctrl.1
CLSID: {13149882-F480-4F6B-8C6A-0764F75B99ED}
Safe for Scripting (Registry): True
Safe for Initialization (Registry): True

This control is marked safe for scripting and safe for initialization,
then Internet Explorer will allow scripting of this control from remote.

Vulnerability:

The 'BackImage' ,'ScriptName', 'ModelName' and 'SRC' properties
can be used to trigger a buffer overflow condition.
The crazytalk4.ocx ActiveX control will load the close CrazyTalk4Native.dll
library and, while constructing a local file path, will call sprintf()
with an insufficient size.

Call stack of main thread
Address Stack Procedure / arguments Called from Frame
0012EE24 023D4FAB msvcrt.sprintf CrazyTal.023D4FA5
0012EE28 0012F180 s = 0012F180
0012EE2C 023F431C format = "%s%s%s"
0012EE30 042A2D6C <%s> = "C:\DOCUME~1\Admin\LOCALS~1\Temp\RLTMP\~RW463\"
0012EE34 0012EF5C <%s> = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
0012EE38 0012EE58 <%s> = ""
0012F164 023D601D CrazyTal.023D4F20

code, CrazyTalk4Native.dll :
.
023D4F80 85C0 test eax,eax
023D4F82 74 38 je short CrazyTal.023D4FBC
023D4F84 8B9C24 2C030000 mov ebx,dword ptr ss:[esp+32C]
023D4F8B 8D4424 1C lea eax,dword ptr ss:[esp+1C]
023D4F8F 8D8C24 20010000 lea ecx,dword ptr ss:[esp+120]
023D4F96 50 push eax
023D4F97 81C6 443B0000 add esi,3B44
023D4F9D 51 push ecx
023D4F9E 56 push esi
023D4F9F 68 1C433F02 push CrazyTal.023F431C ; ASCII "%s%s%s"
023D4FA4 53 push ebx
023D4FA5 FF15 E4F33E02 call dword ptr ds:[<&MSVCRT.sprintf>] ; msvcrt.sprintf
.

As attachment, proof of concept code which overwrites EIP and SEH.

Note:

0:008> lm -vm CrazyTalk4Native
start end module name
021c0000 0220b000 CrazyTalk4Native (deferred)
Image path: C:\PROGRA~1\COMMON~1\REALLU~1\CTPLAY~1\CrazyTalk4Native.dll
Image name: CrazyTalk4Native.dll
Timestamp: Thu May 17 12:13:42 2007 (464C2AD6)
CheckSum: 00048AB2
ImageSize: 0004B000
File version: 4.5.815.1
Product version: 4.0.0.1
File flags: 0 (Mask 3F)
File OS: 4 Unknown Win32
File type: 2.0 Dll
File date: 00000000.00000000
Translations: 0409.04b0
CompanyName: C3D
ProductName: CrazyTalk4 ActiveX Control Module
InternalName: CrazyTalk4
OriginalFilename: CrazyTalk4.OCX
ProductVersion: 4, 0, 0, 1
FileVersion: 4, 5, 815, 1
PrivateBuild: 4, 5, 815, 1
SpecialBuild: 4, 5, 815, 1
FileDescription: CrazyTalk4 Native Control Module
LegalCopyright: Copyright (C) 2005
LegalTrademarks: Copyright (C) 2005
Comments: Copyright (C) 2005

proof of concept: http://retrogod.altervista.org/9sg_dell_poc_nodep.html