[NT] Vulnerability in Windows Media Player Could Allow Remote Code Execution (MS06-024)

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Vulnerability in Windows Media Player Could Allow Remote Code Execution
(MS06-024)
------------------------------------------------------------------------


SUMMARY

Improper handling of PNG images allows attackers to execute arbitrary code
in Windows Media Player.

DETAILS

Vulnerable Systems:
* Windows Media Player for XP on Microsoft Windows XP Service Pack 1
<http://www.microsoft.com/downloads/details.aspx?FamilyId=11372cc0-3da9-49ad-bb08-1493ce3cd0bd> Download the update
* Windows Media Player 9 on Microsoft Windows XP Service Pack 2
<http://www.microsoft.com/downloads/details.aspx?FamilyId=c00be4c3-34ba-4858-90d7-520b7d240e33> Download the update
* Windows Media Player 10 on Microsoft Windows XP Professional x64
Edition
<http://www.microsoft.com/downloads/details.aspx?FamilyId=f59065ec-0279-48ec-ab27-8abca715ac01> Download the update
* Windows Media Player 9 on Microsoft Windows Server 2003
<http://www.microsoft.com/downloads/details.aspx?FamilyId=c00be4c3-34ba-4858-90d7-520b7d240e33> Download the update
* Windows Media Player 10 on Microsoft Windows Server 2003 Service Pack 1

<http://www.microsoft.com/downloads/details.aspx?FamilyId=4f933b0c-7d2d-4049-92da-bbbe97371594> Download the update
* Windows Media Player 10 on Microsoft Windows Server 2003 x64 Edition
<http://www.microsoft.com/downloads/details.aspx?FamilyId=facc7dfe-9b3b-48dd-a068-5bb9c6b60f87> Download the update
* Microsoft Windows 98, Microsoft Windows 98 Second Edition (SE), and
Microsoft Windows Millennium Edition (Me) Review the FAQ section of this
bulletin for details about these operating systems.

* Microsoft Windows Media Player 7.1 when installed on Windows 2000
Service Pack 4
<http://www.microsoft.com/downloads/details.aspx?FamilyId=5abb6258-9468-4188-a178-aa46f100ab61> Download the update
* Microsoft Windows Media Player 9 when installed on Windows 2000 Service
Pack 4 or Windows XP Service Pack 1
<http://www.microsoft.com/downloads/details.aspx?FamilyId=c00be4c3-34ba-4858-90d7-520b7d240e33> Download the update
* Microsoft Windows Media Player 10 when installed on Windows XP Service
Pack 1 or Windows XP Service Pack 2
<http://www.microsoft.com/downloads/details.aspx?FamilyId=0f641572-74fd-4281-953f-6f2f12e001e0> Download the update

Immune Systems:
* Windows Media Player 6.4 on all Microsoft Windows operating systems
* Microsoft Windows Server 2003 for Itanium-based Systems and Microsoft
Windows Server 2003 with SP1 for Itanium-based Systems

Windows Media Player PNG Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0025>
CVE-2006-0025
A remote code execution vulnerability exists in Windows Media Player due
to the way it handles the processing of PNG images. An attacker could
exploit the vulnerability by constructing specially crafted Windows Media
Player content that could potentially allow remote code execution if a
user visits a malicious Web site or opens an email message with malicious
content. An attacker who successfully exploited this vulnerability could
take complete control of an affected system.

Mitigating Factors for Windows Media Player PNG Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0025>
CVE-2006-0025:
* In a Web-based attack scenario, an attacker would have to host a Web
site that contains a Web page that is used to attempt to exploit this
vulnerability. An attacker would have no way to force users to visit a
malicious Web site. Instead, an attacker would have to persuade users to
visit the Web site, typically by getting them to click a link that takes
them to the attacker's site. It could also be possible to display
malicious Web content by using banner advertisements or by using other
methods to deliver Web content to affected systems.

* When using Microsoft Windows 2000 Service Pack 4 with Windows Media
Player 7.1 or Windows XP Service Pack 1 with Windows Media Player for XP,
users are not vulnerable in a Web-based attack scenario. Users are still
vulnerable if a user downloads and installs a malicious Windows Media
Player skin.

* In an e-mail attack scenario, an attacker could exploit the
vulnerability by sending a specially crafted .WMZ file to the user and by
persuading the user to open the file.

* An attacker who successfully exploited this vulnerability could gain
the same user rights as the local user. Users whose accounts are
configured to have fewer user rights on the system could be less affected
than users who operate with administrative user rights.

Workarounds for Windows Media Player PNG Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0025>
CVE-2006-0025:
Microsoft has tested the following workarounds. While these workarounds
will not correct the underlying vulnerability, they help block known
attack vectors. When a workaround reduces functionality, it is identified
in the following section.

There are several different attack vectors that Microsoft has identified
for this vulnerability. Each attack vector has a different workaround.

Note The following steps require Administrator privileges. We recommend
that you restart the computer after you apply this workaround.
Alternatively, you can log out and log back in after you apply the
workaround.

Modify the Access Control List on the DirectX Filter Graph no thread
Registry Key
Modifying the Access Control List on the Filter Graph no thread registry
key helps protect the affected system from attempts to exploit this
vulnerability. To modify the Filter Graph no Thread Splitter registry key,
follow these steps.

Note Using Registry Editor incorrectly can cause serious problems that may
require you to reinstall your operating system. Microsoft cannot guarantee
that problems resulting from the incorrect use of Registry Editor can be
solved. Use Registry Editor at your own risk. For information about how to
edit the registry, view the "Changing Keys and Values" Help topic in
Registry Editor (Regedit.exe) or view the "Add and Delete Information in
the Registry" and "Edit Registry Data" Help topics in Regedt32.exe.

Note We recommend backing up the registry before you edit it.

For Windows 2000

Note Make a note of the permissions that are listed in the dialog box so
that you can restore them to their original values at a later time

1. Click Start, click Run, type regedt32, and then click OK.
2. Expand HKEY_CLASSES_ROOT, expand CLSID, and then click
{E436EBB8-524F-11CE-9F53-0020AF0BA770}.
3. Click Security, and then click Permissions.
4. Click to clear the Allow Inheritable Permissions from the parent to
propagate to this object check box. You are prompted to click Copy,
Remove, or Cancel. Click Remove, and then click OK.
5. You receive a message that states that no one will be able to access
this registry key. Click Yes when you are prompted to do so.

For Windows XP Service Pack 1 or later operating systems

Note Make a note of the permissions that are listed in the dialog box so
that you can restore them to their original values at a later time.

1. Click Start, click Run, type "regedit" (without the quotation marks),
and then click OK.
2. Expand HKEY_CLASSES_ROOT, expand CLSID, and then click
{E436EBB8-524F-11CE-9F53-0020AF0BA770}.
3. Click Edit, and then click Permissions.
4. Click Advanced.
5. Click to clear the Inherit from parent the permission entries that
apply to child objects. Include these with entries explicitly defined here
check box. You are prompted to click Copy, Remove, or Cancel. Click
Remove, and then check OK.
6. You receive a message that states that no one will be able to access
this registry key. Click Yes, and then click OK to close the Permissions
for {E436EBB8-524F-11CE-9F53-0020AF0BA770} dialog box.

Note If you have backed up and removed the DirectX Filter Graph no thread
registry key, you do not need to modify the Access Control List on the
DirectX Filter Graph no thread registry key.

Impact of Workaround: This workaround disables image rendering and audio
and video playback in any number of DirectX-enabled applications

Backup and remove the DirectX Filter Graph no thread registry key
Removing the Filter Graph no thread registry key helps protect the
affected system from attempts to exploit this vulnerability. To backup and
remove the Filter Graph no thread registry key, follow these steps:

Note Using Registry Editor incorrectly can cause serious problems that may
require you to reinstall your operating system. Microsoft cannot guarantee
that problems resulting from the incorrect use of Registry Editor can be
solved. Use Registry Editor at your own risk. For information about how to
edit the registry, view the "Changing Keys and Values" Help topic in
Registry Editor (Regedit.exe) or view the "Add and Delete Information in
the Registry" and "Edit Registry Data" Help topics in Regedt32.exe.

Note We recommend backing up the registry before you edit it.

1. Click Start, click Run, type regedit" (without the quotation marks),
and then click OK.
2. Expand HKEY_CLASSES_ROOT, expand CLSID, and then click
{E436EBB8-524F-11CE-9F53-0020AF0BA770}.
3. Click File, and then click Export.
4. In the Export Registry File dialog box, type a file name in the File
Name box, and then click Save.
5. Click Edit, and then click Delete to remove the registry key.
6. In the Confirm Key Delete dialog box, you receive a Are you sure you
want to delete this key and all of its sub keys message. Click Yes.

Note If you have backed up and remove the DirectX Filter Graph no thread
registry key, you do not need to modify the Access Control List on the
DirectX Filter Graph no thread registry key.

Impact of Workaround: This workaround disables image rendering and audio
and video playback in any number of DirectX-enabled applications.

Un-register Wmp.dll
Un-registering the Wmp.dll registry key helps protect the affected system
from attempts to exploit this vulnerability. To modify the Wmp.dll
registry key, follow these steps.

1. Click Start, click Run, type "regsvr32 -u %windir%\system32\wmp.dll"
(without the quotation marks), and then click OK.
2. When a dialog box appears that confirms that the process has been
successful, click OK.
3. Select the File Types tab.

Impact of Workaround: This workaround disables the Windows Media Player
and applications that use the embedded Windows Media ActiveX Control.

Disassociate the WMZ file extensions
Disassociation of WMZ in Windows prevents previewing or opening WMZ files
that point to malformed PNG files.

1. Launch Windows Explorer.
2. Click Tools, Folder Options and then Select the File Types tab.
3. Scroll to find the WMZ file extension and then click Delete.

Note Removing the skin file association needs to be done in addition to at
least one of the workarounds listed above.

Impact of Workaround: This workaround prevents users from applying skin
files to Windows Media Player by double clicking on them. Users can still
apply skin files that are in their default skins directory.

FAQ for Windows Media Player PNG Vulnerability -
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0025>
CVE-2006-0025:
What is the scope of the vulnerability?
A remote code execution vulnerability exists in Windows Media Player due
to the way it handles the processing of PNG images. An attacker could
exploit the vulnerability by constructing specially crafted Windows Media
Player content that could potentially allow remote code execution if a
user visits a malicious Web site or clicks on a specially crafted WMZ file
in an email message. An attacker who successfully exploited this
vulnerability could take complete control of an affected system.

If a user is logged on with administrative user rights, an attacker who
successfully exploited this vulnerability could take complete control of
an affected system. An attacker could then install programs; view, change,
or delete data; or create new accounts with full user rights. Users whose
accounts are configured to have fewer user rights on the system could be
less affected than users who operate with administrative user rights.

What causes the vulnerability?
An unchecked buffer in the PNG processing code within Windows Media
Player.

What is Windows Media Player?
Windows Media Player is a feature of the Windows operating system for
personal computers. It is used for playing audio and video.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could take
complete control of the affected system.

How could an attacker exploit the vulnerability?
In a Web-based attack scenario, an attacker would have to host a Web site
that contains a Web page that is used to attempt to exploit this
vulnerability. An attacker would have no way to force users to visit a
malicious Web site. Instead, an attacker would have to persuade them to
visit the Web site, typically by getting them to click a link that takes
them to the attacker's site. It could also be possible to display
malicious Web content by using banner advertisements or by using other
methods to deliver Web content to affected systems.

In an e-mail attack scenario, an attacker could exploit the vulnerability
by sending a specially crafted file to the user and by persuading the user
to open the file.

What systems are primarily at risk from the vulnerability?
Workstations and terminal servers are primarily at risk. Servers could be
at more risk if users who do not have sufficient administrative
permissions are given the ability to log on to servers and to run
programs. However, best practices strongly discourage allowing this.

Are Windows 98, Windows 98 Second Edition, or Windows Millennium Edition
critically affected by this vulnerability?
Yes. This vulnerability is critical for Windows Media Player 9 on Windows
98 Second Edition, and Windows Millennium Edition. Critical security
updates for these platforms may not be available concurrently with the
other security updates provided as part of this security bulletin. They
will be made available as soon as possible following the release. When
these security updates are available, you will be able to download them
only from the Windows Update Web site. For more information about severity
ratings, visit the following Web site.

What does the update do?
The update removes the vulnerability by modifying the way that the Windows
Media Player validates the processing code before it passes it to the
allocated buffer.

When this security bulletin was issued, had this vulnerability been
publicly disclosed?
No. Microsoft received information about this vulnerability through
responsible disclosure. Microsoft had not received any information to
indicate that this vulnerability had been publicly disclosed when this
security bulletin was originally issued.

When this security bulletin was issued, had Microsoft received any reports
that this vulnerability was being exploited?
No. Microsoft had not received any information to indicate that this
vulnerability had been publicly used to attack customers and had not seen
any examples of proof of concept code published when this security
bulletin was originally issued.


ADDITIONAL INFORMATION

The information has been provided by Microsoft Security.
The original article can be found at:
<http://www.microsoft.com/technet/security/Bulletin/MS06-024.mspx>
http://www.microsoft.com/technet/security/Bulletin/MS06-024.mspx



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