Microsoft Security Bulletin MS14-033 - Important

Vulnerability in Microsoft XML Core Services Could Allow Information Disclosure (2966061)

Published: June 10, 2014 | Updated: July 10, 2014

Version: 1.1

General Information

Executive Summary

This security update resolves a privately reported vulnerability in Microsoft Windows. The vulnerability could allow information disclosure if a logged on user visits a specially crafted website that is designed to invoke Microsoft XML Core Services (MSXML) through Internet Explorer. In all cases, however, an attacker would have no way to force users to visit such websites. Instead, an attacker would have to convince users to visit a website, typically by getting them to click a link in an email message or in an Instant Messenger request that takes users to the attacker's website.

This security update for Microsoft XML Core Services 3.0 and Microsoft XML Core Services 6.0 is rated Important for affected releases of Microsoft Windows clients and Low for affected releases of Microsoft Windows servers. For more information, see the Affected and Non-Affected Software section below.

The security update addresses the vulnerability by modifying how Microsoft XML Core Services enforces user access controls. For more information about the vulnerability, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability later in this bulletin.

Recommendation. Most customers have automatic updating enabled and will not need to take any action because this security update will be downloaded and installed automatically. Customers who have not enabled automatic updating need to check for updates and install this update manually. For information about specific configuration options in automatic updating, see Microsoft Knowledge Base Article 294871.

For administrators and enterprise installations, or end users who want to install this security update manually, Microsoft recommends that customers apply the update at the earliest opportunity using update management software, or by checking for updates using the Microsoft Update service.

See also the section, Detection and Deployment Tools and Guidance, later in this bulletin.

Knowledge Base Article

• Knowledge Base Article: 2966061
• File Information: Yes
• SHA1/SHA2 hashes: Yes
• Known issues: None

Affected and Non-Affected Software

The following software has been tested to determine which versions or editions are affected. Other versions or editions are either past their support life cycle or are not affected. To determine the support life cycle for your software version or edition, see Microsoft Support Lifecycle.

Affected Software 

^[1]This update is for systems that have the 2919355 update installed. See the Update FAQ for more information. ^[2]This update is for systems that do not have the 2919355 update installed. This update is not available via the Microsoft Download Center. See the Update FAQ for more information. ^[3]This update is available via Windows Update.

Non-Affected Software

Update FAQ

There are multiple updates listed for Windows 8.1 and Windows Server 2012 R2. Do I need to install both updates?
No. Depending on how your system is configured to receive updates, only one of the updates for a given edition of Windows 8.1 or Windows Server 2012 R2 will apply.

For systems running Windows 8.1 or Windows Server 2012 R2:

• The 2939576 update is for systems that already have the 2919355 update installed.
• The 2966631 update is for systems without the 2919355 update installed. Note that the 2966631 update is only available for customers managing updates using Windows Server Update Services (WSUS), Windows Intune, or System Center Configuration Manager.

What version of Microsoft XML Core Services is installed on my system? 
Some versions of Microsoft XML Core Services are included with Microsoft Windows; others are installed with non-operating system software from Microsoft or third-party providers. Some are also available as separate downloads. The following table shows which of the affected versions of MSXML are included with affected versions of Microsoft Windows and which are installed with additional Microsoft or third-party software.

Note For information on which versions are supported by Microsoft, see Microsoft Knowledge Base Article 269238.

What is Microsoft XML Core Services (MSXML)? 
Microsoft XML Core Services (MSXML) allows customers who use JScript, Visual Basic Scripting Edition (VBScript), and Microsoft Visual Studio 6.0 to develop XML-based applications that provide interoperability with other applications that adhere to the XML 1.0 standard. For more information, see the MSDN article, MSXML.

I am using an older release of the software discussed in this security bulletin. What should I do? 
The affected software listed in this bulletin has been tested to determine which releases are affected. Other releases are past their support life cycle. For more information about the product lifecycle, see the Microsoft Support Lifecycle website.

It should be a priority for customers who have older releases of the software to migrate to supported releases to prevent potential exposure to vulnerabilities. To determine the support lifecycle for your software release, see Select a Product for Lifecycle Information. For more information about service packs for these software releases, see Service Pack Lifecycle Support Policy.

Customers who require custom support for older software must contact their Microsoft account team representative, their Technical Account Manager, or the appropriate Microsoft partner representative for custom support options. Customers without an , Premier, or Authorized Contract can contact their local Microsoft sales office. For contact information, see the Microsoft Worldwide Information website, select the country in the Contact Information list, and then click Go to see a list of telephone numbers. When you call, ask to speak with the local Premier Support sales manager. For more information, see the Microsoft Support Lifecycle Policy FAQ.

Severity Ratings and Vulnerability Identifiers

The following severity ratings assume the potential maximum impact of the vulnerability. For information regarding the likelihood, within 30 days of this security bulletin's release, of the exploitability of the vulnerability in relation to its severity rating and security impact, please see the Exploitability Index in the June bulletin summary. For more information, see Microsoft Exploitability Index.

MSXML Entity URI Vulnerability - CVE-2014-1816

An information disclosure vulnerability exists in the way that Microsoft Windows parses XML content. The vulnerability may allow an attacker to access information not otherwise allowed.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2014-1816.

Mitigating Factors

Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation:

• In a web-based attack scenario, an attacker could exploit the vulnerability by hosting a specially crafted website that is designed to invoke MSXML through Internet Explorer. This could also include compromised websites and websites that accept or host user-provided content or advertisements. These websites could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit such websites. Instead, an attacker would have to convince users to visit the website, typically by getting them to click a link in an email message or in an Instant Messenger request that takes users to the attacker's website.
• By default, Internet Explorer on Windows Server 2003, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, and Windows Server 2012 R2 runs in a restricted mode that is known as Enhanced Security Configuration. This mode mitigates this vulnerability. See the FAQ section for this vulnerability for more information about Internet Explorer Enhanced Security Configuration.

Workarounds

Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:

• Prevent MSXML 3.0 binary behaviors from being used in Internet Explorer

  You can disable attempts to use a specific binary behavior in Internet Explorer by setting the kill bit for the behavior in the registry.

  Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

  To set the kill bits for CLSIDs with value of {f5078f39-c551-11d3-89b9-0000f81fe221} and {f6d90f16-9c73-11d3-b32e-00c04f990bb4}, paste the following text in a text editor such as Notepad. Then, save the file by using the .reg file name extension.

  Windows Registry Editor Version 5.00
  [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{f5078f39-c551-11d3-89b9-0000f81fe221}]
  "Compatibility Flags"=dword:04000400
  
  [HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\ActiveX Compatibility\{f5078f39-c551-11d3-89b9-0000f81fe221}]
  "Compatibility Flags"=dword:04000400
  
  Windows Registry Editor Version 5.00
  [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{f6d90f16-9c73-11d3-b32e-00c04f990bb4}]
  "Compatibility Flags"=dword:04000400
  
  [HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\ActiveX Compatibility\{f6d90f16-9c73-11d3-b32e-00c04f990bb4}]
  "Compatibility Flags"=dword:04000400
  

  You can apply this .reg file to individual systems by double-clicking it. You can also apply it across domains by using Group Policy. For more information about Group Policy, see the TechNet article, Group Policy Collection.

  Note:
  You must restart Internet Explorer for your changes to take effect.

  Impact of workaround. Websites that use the XMLHTTP 3.0 ActiveX controls may no longer display or function correctly in Internet Explorer.

  How to undo the workaround. Delete the registry keys previously added in implementing this workaround.

   

• Configure Internet Explorer to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone

  You can help protect against exploitation of this vulnerability by changing your settings to prompt before running Active Scripting or to disable Active Scripting in the Internet and Local intranet security zone. To do this, perform the following steps:

  1. In Internet Explorer, click Internet Options on the Tools menu.

  2. Click the Security tab.

  3. Click Internet, and then click Custom Level.

  4. Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.

  5. Click Local intranet, and then click Custom Level.

  6. Under Settings, in the Scripting section, under Active Scripting, click Prompt or Disable, and then click OK.

  7. Click OK two times to return to Internet Explorer.

     Note:
     Disabling Active Scripting in the Internet and Local intranet security zones may cause some websites to work incorrectly. If you have difficulty using a website after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly.

  Impact of workaround. There are side effects to prompting before running Active Scripting. Many websites that are on the Internet or on an intranet use Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use Active Scripting to provide menus, ordering forms, or even account statements. Prompting before running Active Scripting is a global setting that affects all Internet and intranet sites. You will be prompted frequently when you enable this workaround. For each prompt, if you feel you trust the site that you are visiting, click Yes to run Active Scripting. If you do not want to be prompted for all these sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone".

  Add sites that you trust to the Internet Explorer Trusted sites zone

  After you set Internet Explorer to require a prompt before it runs ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted websites exactly as you do today, while helping to protect you from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

  To do this, perform the following steps:

  1. In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

  2. In the Select a web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

  3. If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

  4. In the Add this website to the zone box, type the URL of a site that you trust, and then click Add.

  5. Repeat these steps for each site that you want to add to the zone.

  6. Click OK two times to accept the changes and return to Internet Explorer.

     Note:
     Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update.\

• Set Internet and Local intranet security zone settings to "High" to block ActiveX Controls and Active Scripting in these zones

  You can help protect against exploitation of this vulnerability by changing your settings for the Internet security zone to block ActiveX controls and Active Scripting. You can do this by setting your browser security to High.

  To raise the browsing security level in Internet Explorer, perform the following steps:

  1. On the Internet Explorer Tools menu, click Internet Options.

  2. In the Internet Options dialog box, click the Security tab, and then click Internet.

  3. Under Security level for this zone, move the slider to High. This sets the security level for all websites you visit to High. (If no slider is visible, click Default Level, and then move the slider to High.)

  4. Click Local intranet.

  5. Under Security level for this zone, move the slider to High. This sets the security level for all websites you visit to High.

     Note:
     Click OK to accept the changes and return to Internet Explorer.\ Setting the level to High may cause some websites to work incorrectly. If you have difficulty using a website after you change this setting, and you are sure the site is safe to use, you can add that site to your list of trusted sites. This will allow the site to work correctly even with the security setting set to High.

  Impact of workaround. There are side effects to blocking ActiveX Controls and Active Scripting. Many websites that are on the Internet or on an intranet use ActiveX or Active Scripting to provide additional functionality. For example, an online e-commerce site or banking site may use ActiveX Controls to provide menus, ordering forms, or even account statements. Blocking ActiveX Controls or Active Scripting is a global setting that affects all Internet and intranet sites. If you do not want to block ActiveX Controls or Active Scripting for such sites, use the steps outlined in "Add sites that you trust to the Internet Explorer Trusted sites zone".

  Add sites that you trust to the Internet Explorer Trusted sites zone

  After you set Internet Explorer to block ActiveX controls and Active Scripting in the Internet zone and in the Local intranet zone, you can add sites that you trust to the Internet Explorer Trusted sites zone. This will allow you to continue to use trusted websites exactly as you do today, while helping to protect yourself from this attack on untrusted sites. We recommend that you add only sites that you trust to the Trusted sites zone.

  To do this, perform the following steps:

  1. In Internet Explorer, click Tools, click Internet Options, and then click the Security tab.

  2. In the Select a web content zone to specify its current security settings box, click Trusted Sites, and then click Sites.

  3. If you want to add sites that do not require an encrypted channel, click to clear the Require server verification (https:) for all sites in this zone check box.

  4. In the Add this website to the zone box, type the URL of a site that you trust, and then click Add.

  5. Repeat these steps for each site that you want to add to the zone.

  6. Click OK two times to accept the changes and return to Internet Explorer.

     Note:
     Add any sites that you trust not to take malicious action on your system. Two in particular that you may want to add are *.windowsupdate.microsoft.com and *.update.microsoft.com. These are the sites that will host the update, and it requires an ActiveX Control to install the update. \

   

FAQ

What is the scope of the vulnerability?
This is an information disclosure vulnerability.

What causes the vulnerability?
The vulnerability is caused when Microsoft XML Core Services (MSXML) parses XML content and does not properly enforce user access controls.

**What is the component affected by the vulnerability? ** The vulnerability affects Microsoft XML Core Services (MSXML), which allows customers who use JScript, Visual Basic Scripting Edition (VBScript), and Microsoft Visual Studio 6.0 to develop XML-based applications that provide interoperability with other applications that adhere to the XML 1.0 standard. For more information, see the Microsoft Developer Network article, MSXML.

What is Microsoft XML Core Services (MSXML)?
Microsoft XML Core Services (MSXML) allows customers who use JScript, Visual Basic Scripting Edition (VBScript), and Microsoft Visual Studio 6.0 to develop XML-based applications that provide interoperability with other applications that adhere to the XML 1.0 standard. For more information, see the MSDN article, MSXML.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could obtain the user’s personal information from the local system.

How could an attacker exploit the vulnerability?
An attacker could exploit the vulnerability by hosting a specially crafted website that is designed to invoke MSXML through Internet Explorer. This could also include compromised websites and websites that accept or host user-provided content or advertisements. These websites could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit such websites. Instead, an attacker would have to convince users to visit a website, typically by getting them to click a link in an email message or in an Instant Messenger request that takes users to the attacker's website. It could also be possible to display specially crafted web content by using banner advertisements or by using other methods to deliver web content to affected systems.

Non-Microsoft web applications and services that use the MSXML library for parsing XML could also be vulnerable to this attack.

What systems are primarily at risk from the vulnerability?
This vulnerability requires that a user be logged on and visiting a website for any malicious action to occur. Therefore, any systems where Internet Explorer is used frequently, such as workstations or terminal servers, are at the most risk from this vulnerability.

I am running Internet Explorer on Windows Server 2003, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, or Windows Server 2012 R2. Does this mitigate this vulnerability?
Yes. By default, Internet Explorer on Windows Server 2003, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, and Windows Server 2012 R2 runs in a restricted mode that is known as Enhanced Security Configuration. Enhanced Security Configuration is a group of preconfigured settings in Internet Explorer that can reduce the likelihood of a user or administrator downloading and running specially crafted web content on a server. This is a mitigating factor for websites that you have not added to the Internet Explorer Trusted sites zone.

What does the update do?
The update addresses the vulnerability by modifying how Microsoft XML Core Services enforces user access controls.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through coordinated vulnerability disclosure.

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 when this security bulletin was originally issued.

Detection and Deployment Tools and Guidance

Several resources are available to help administrators deploy security updates. 

• Microsoft Baseline Security Analyzer (MBSA) lets administrators scan local and remote systems for missing security updates and common security misconfigurations. 
• Windows Server Update Services (WSUS), Systems Management Server (SMS), and System Center Configuration Manager help administrators distribute security updates. 
• The Update Compatibility Evaluator components included with Application Compatibility Toolkit aid in streamlining the testing and validation of Windows updates against installed applications. 

For information about these and other tools that are available, see Security Tools for IT Pros. 

Security Update Deployment

Windows Server 2003 (all editions)

Reference Table

The following table contains the security update information for this software.

Windows Vista (all editions)

Reference Table

The following table contains the security update information for this software.

Windows Server 2008 (all editions)

Reference Table

The following table contains the security update information for this software.

Windows 7 (all editions)

Reference Table

The following table contains the security update information for this software.

Windows Server 2008 R2 (all editions)

Reference Table

The following table contains the security update information for this software.

Windows 8 and Windows 8.1 (all editions)

Reference Table

The following table contains the security update information for this software.

Windows Server 2012 and Windows Server 2012 R2 (all editions)

Reference Table

The following table contains the security update information for this software.

Windows RT and Windows RT 8.1 (all editions)

Reference Table

The following table contains the security update information for this software.

Acknowledgments

Microsoft thanks the following for working with us to help protect customers:

• Christian Kulenkampff for reporting the MSXML Entity URI Vulnerability (CVE-2014-1816)

Other Information

Microsoft Active Protections Program (MAPP)

To improve security protections for customers, Microsoft provides vulnerability information to major security software providers in advance of each monthly security update release. Security software providers can then use this vulnerability information to provide updated protections to customers via their security software or devices, such as antivirus, network-based intrusion detection systems, or host-based intrusion prevention systems. To determine whether active protections are available from security software providers, please go to the active protections websites provided by program partners, listed in Microsoft Active Protections Program (MAPP) Partners.

Support

How to obtain help and support for this security update

• Help installing updates: Support for Microsoft Update
• Security solutions for IT professionals: TechNet Security Troubleshooting and Support
• Help protect your computer that is running Windows from viruses and malware: Virus Solution and Security Center
• Local support according to your country: International Support

Disclaimer

The information provided in the Microsoft Knowledge Base is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

Revisions

• V1.0 (June 10, 2014): Bulletin published.
• V1.1 (July 10, 2014): Bulletin revised to remove the prerequisite requirement for the MSXML 6.0 update on Windows Server 2003 systems. This is an informational change only. Customers who have already successfully updated their systems do not need to take any action.

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