DirectX Vulnerability

[ZWarrior]

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Title:      Unchecked Buffer in DirectX Could Enable System Compromise (819696)
Released:   23 July 2003
Revised:    20 August 2003 (version 2.0)

Software:   Microsoft DirectX(r) 5.2 on Windows 98
            Microsoft DirectX 6.1 on Windows 98 SE
            Microsoft DirectX 7.1 on Windows Millennium Edition
            Microsoft DirectX 7.0 on Windows 2000
            Microsoft DirectX 8.0, 8.0a, 8.1, 8.1a, and 8.1b when  
             installed on Windows 98, Windows 98 SE, Windows
            Millennium Edition or Windows 2000
            Microsoft DirectX 8.1 on Windows XP or
             Windows Server 2003
            Microsoft DirectX 9.0a when installed on Windows 98,
             Windows 98 SE, Windows Millennium Edition (Windows Me),
             Windows 2000, Windows XP, or 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 Bulletin at:
http://www.microsoft.com/technet/security/bulletin/MS03-030.asp
http://www.microsoft.com/security/security_bulletins/MS03-030.asp
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Reason for Revision:
====================
Subsequent to the original release of this bulletin, customers requested that we support additional versions of DirectX that were not covered by the original patches. This bulletin has been updated to provide information about this new patch.

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 could 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/MS03-30.asp
   for information on obtaining this patch.

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

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