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Message-ID: <011501c361c7$c4f01380$0200000a@JumperLappy>
Date: Wed, 13 Aug 2003 20:21:50 +0200
From: "Thor Larholm" <thor@...x.com>
To: "Tri Huynh" <trihuynh@...up.com>, <bugtraq@...urityfocus.com>
Cc: <full-disclosure@...ts.netsys.com>
Subject: Re: Microsoft MCWNDX.OCX ActiveX buffer overflow
The MCWNDX.OCX binary is digitally signed by Microsoft, and as such you can
plant it on the users machine just by pointing the codebase attribute of your
OBJECT tag to an archived copy of the file on your own server.
This also applies to other outdated ActiveX controls, even when a newer
(patched) version exists and is installed on the users machine you can still
re-introduce the old, buggy version since it is digitally signed by Microsoft.
Regards
Thor Larholm
PivX Solutions, LLC - Senior Security Researcher
----- Original Message -----
From: "Tri Huynh" <trihuynh@...up.com>
Subject: [Full-Disclosure] Microsoft MCWNDX.OCX ActiveX buffer overflow
>
>
> Microsoft MCWNDX.OCX ActiveX buffer overflow
> =================================================
>
> PROGRAM: MICROSOFT MCIWNDX.OCX ACTIVEX BUFFER OVERFLOW
> HOMEPAGE: www.microsoft.com
> VULNERABLE VERSIONS: MCWNDX is an ActiveX shipped with Visual Studio 6 to
> support multimedia programming.
>
> DESCRIPTION
> =================================================
>
> MCWNDX is an activeX shipped with Visual Studio 6 to
> support multimedia programming. Although not many people use it anymore,
> however it still can be called through CLSID in a website and passing a
> large amount of data to the activex will cause an buffer overflow.
>
> Since this Activex is only shipped with VIsual Studio 6.0, so only
> people who are having Visual Studio 6.0 will be affected or people
> who are still using old multimedia programs coded in Visual Studio 6.0
> (In my PC, the last date the ActiveX is patched is in 1996 ! I am using
> VS Sp 4)
>
>
> DETAILS
> =================================================
> The ActiveX has a property called "Filename" which is used to specify
> the .mci file to load. However if it is passed with a very large
> string(640KB
> is good enough :-) ), it will cause a bufferoverflow. (I can't overwrite the
> EIP using this overflow in my XP, however it doesn't mean the problem can't
> be exploited)
>
> Microsoft has been noticed but since the hole is maybe minor to them so
> they don't response to me even a short sentence like "Thank you !"
>
>
>
> WORKAROUND
> =================================================
>
> Delete the file MCWNDX.ocx in your SYSTEM32 directory if you are
> using 2000 or XP or in your SYSTEM directory if you are using WIN ME or
> below
>
>
> CREDITS
> =================================================
>
> Discovered by Tri Huynh from Sentry Union
>
>
> DISLAIMER
> =================================================
>
> The information within this paper may change without notice. Use of
> this information constitutes acceptance for use in an AS IS condition.
> There are NO warranties with regard to this information. In no event
> shall the author be liable for any damages whatsoever arising out of
> or in connection with the use or spread of this information. Any use
> of this information is at the user's own risk.
>
>
> FEEDBACK
> =================================================
>
> Please send suggestions, updates, and comments to: trihuynh@...up.com
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