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Title:      Unchecked Buffer in DirectX Could Enable System 
            Compromise (819696)
Date:       July 23, 2003
Software:   Microsoft DirectX(r) 5.2 on Windows 98 
            Microsoft DirectX 6.1 on Windows 98 SE 
            Microsoft DirectX 7.0a on Windows Millennium Edition 
            Microsoft DirectX 7.0 on Windows 2000 
            Microsoft DirectX 8.1 on Windows XP 
            Microsoft DirectX 8.1 on Windows Server 2003 
            Microsoft DirectX 9.0a when installed on Windows 98 
            Microsoft DirectX 9.0a when installed on Windows 98 SE 
            Microsoft DirectX 9.0a when installed on Windows
            Millennium Edition 
            Microsoft DirectX 9.0a when installed on Windows 2000 
            Microsoft DirectX 9.0a when installed on Windows XP 
            Microsoft DirectX(r) 9.0a when installed on Windows 
            Server 2003 
            Microsoft Windows NT 4.0 Server with either Windows
            Media Player 6.4 or Internet Explorer 6 Service Pack 1 
            installed. 
            Microsoft Windows NT 4.0, Terminal Server Edition with 
            either Windows Media Player 6.4 or Internet Explorer 6 
            Service Pack 1 installed.

Impact:     Allow an attacker to execute code on a user's system 
Max Risk:   Critical
Bulletin:   MS03-030

Microsoft encourages customers to review the Security Bulletins at: 
http://www.microsoft.com/technet/security/bulletin/MS03-030.asp
http://www.microsoft.com/security/security_bulletins/ms03-030.asp
- ----------------------------------------------------------------------

Issue:
======
DirectX consists of a set of low-level Application Programming 
Interfaces (APIs) that are used by Windows programs for multimedia 
support. Within DirectX, the DirectShow technology performs client-
side audio and video sourcing, manipulation, and rendering. 

There are two buffer overruns with identical effects in the 
function used by DirectShow to check parameters in a Musical 
Instrument Digital Interface (MIDI) file. A security vulnerability 
results because it would be possible for a malicious user to 
attempt to exploit these flaws and execute code in the security 
context of the logged-on user. 

An attacker could seek to exploit this vulnerability by creating a 
specially crafted MIDI file designed to exploit this vulnerability 
and then host it on a Web site or on a network share, or send it by 
using an HTML-based e-mail. In the case where the file was hosted 
on a Web site or network share, the user would need to open the 
specially crafted file. If the file was embedded in a page the 
vulnerability could be exploited when a user visited the Web page. 
In the HTML-based e-mail case, the vulnerability could be exploited 
when a user opened or previewed the HTML-based e-mail. A successful 
attack could cause DirectShow, or an application making use of 
DirectShow, to fail. A successful attack could also cause an 
attacker's code to run on the user's computer in the security 
context of the user. 

Mitigating Factors:
====================
- - By default, Internet Explorer on Windows Server 2003 runs in 
Enhanced Security Configuration. This default configuration of 
Internet Explorer blocks the e-mail-based vector of this attack 
because Microsoft Outlook Express running on Windows Server 2003 by 
default reads e-mail in plain text. If Internet Explorer Enhanced 
Security Configuration were disabled, the protections put in place 
that prevent this vulnerability from being exploited would be 
removed.
- - In the Web-based attack scenario, the attacker would have to host 
a Web site that contained a Web page used to exploit these 
vulnerabilities. An attacker would have no way to force users to 
visit a malicious Web site outside the HTML-based e-mail vector. 
Instead, the attacker would need to lure them there, typically by 
getting them to click a link that would take them to the attacker's 
site. 
- -The combination of the above means that on Windows Server 2003 an 
administrator browsing only to trusted sites should be safe from 
this vulnerability.
- - Code executed on the system would only run under the privileges 
of the logged-on user.

Risk Rating:
============
 - Critical

Patch Availability:
===================
 - A patch is available to fix this vulnerability. Please read the 
   Security Bulletins at
   http://www.microsoft.com/technet/security/bulletin/ms03-030.asp
   http://www.microsoft.com/security/security_bulletins/ms03-030.asp
   for information on obtaining this patch.

Acknowledgment:
===============
 - eEye Digital Security, http://www.eeye.com


- ---------------------------------------------------------------------

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