Security Bulletin

Microsoft Security Bulletin MS13-068 - Critical

Vulnerability in Microsoft Outlook Could Allow Remote Code Execution (2756473)

Published: September 10, 2013 | Updated: September 10, 2013

Version: 1.0

General Information

Executive Summary

This security update resolves a privately reported vulnerability in Microsoft Outlook. The vulnerability could allow remote code execution if a user opens or previews a specially crafted email message using an affected edition of Microsoft Outlook. 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 impacted than users who operate with administrative user rights.

This security update is rated Critical for all supported editions of Microsoft Outlook 2007 and Microsoft Outlook 2010. For more information, see the subsection, Affected and Non-Affected Software, in this section.

The security update addresses the vulnerability by correcting the way that Microsoft Outlook parses specially crafted S/MIME email messages. For more information about the vulnerabilities, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability entry under the next section, Vulnerability Information.

Recommendation. Customers can configure automatic updating to check online for updates from Microsoft Update by using the Microsoft Update service. Customers who have automatic updating enabled and configured to check online for updates from Microsoft Update typically 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 from Microsoft Update 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 immediately 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 2756473
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

Microsoft Office

Microsoft Office Suite and Other Software Component Maximum Security Impact Aggregate Severity Rating Updates Replaced
Microsoft Office 2007 Service Pack 3 Microsoft Outlook 2007 Service Pack 3\ (2825999) Remote Code Execution Critical 2288953 in MS10-064
Microsoft Office 2010 Service Pack 1 (32-bit editions) Microsoft Outlook 2010 Service Pack 1 (32-bit editions)\ (2794707) Remote Code Execution Critical None
Microsoft Office 2010 Service Pack 2 (32-bit editions) Microsoft Outlook 2010 Service Pack 2 (32-bit editions)\ (2794707) Remote Code Execution Critical None
Microsoft Office 2010 Service Pack 1 (64-bit editions) Microsoft Outlook 2010 Service Pack 1 (64-bit editions)\ (2794707) Remote Code Execution Critical None
Microsoft Office 2010 Service Pack 2 (64-bit editions) Microsoft Outlook 2010 Service Pack 2 (64-bit editions)\ (2794707) Remote Code Execution Critical None

Non-Affected Software 

Office and Other Software
Microsoft Outlook 2003 Service Pack 3
Microsoft Outlook 2013 (32-bit editions)
Microsoft Outlook 2013 (64-bit editions)
Microsoft Outlook 2013 RT

Update FAQ

The Microsoft Office component discussed in this article is part of the Microsoft Office Suite that I have installed on my system; however, I did not choose to install this specific component. Will I be offered this update? 
Yes, if the component discussed in this bulletin was delivered with the version of the Microsoft Office Suite installed on your system, the system will be offered updates for it whether the component is installed or not. The detection logic used to scan for affected systems is designed to check for updates for all components that were delivered with the particular Microsoft Office Suite and to offer the updates to a system. Users who choose not to apply an update for a component that is not installed, but is delivered with their version of the Microsoft Office Suite, will not increase the security risk of that system. On the other hand, users who do choose to install the update will not have a negative impact on the security or performance of a system.

Does the offer to update a non-vulnerable version of Microsoft Office constitute an issue in the Microsoft update mechanism? 
No. The update mechanism is functioning correctly in that it detects a product version for the applicable software on the system that is within the range of product versions that the update applies to and thus, offers the update.

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 Alliance, 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.

Vulnerability Information

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 September bulletin summary. For more information, see Microsoft Exploitability Index.

Affected Software Message Certificate Vulnerability - CVE-2013-3870 Aggregate Severity Rating
Microsoft Outlook 2007 Service Pack 3 Critical \ Remote Code Execution Critical 
Microsoft Outlook 2010 Service Pack 1 (32-bit editions) Critical \ Remote Code Execution Critical 
Microsoft Outlook 2010 Service Pack 2 (32-bit editions) Critical \ Remote Code Execution Critical 
Microsoft Outlook 2010 Service Pack 1 (64-bit editions) Critical \ Remote Code Execution Critical 
Microsoft Outlook 2010 Service Pack 2 (64-bit editions) Critical \ Remote Code Execution Critical 

Message Certificate Vulnerability - CVE-2013-3870

A remote code execution vulnerability exists in the way that Microsoft Outlook parses specially crafted S/MIME email messages. 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.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2013-3870.

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:

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

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:

  • Disable the Reading Pane in Outlook 2007

    Disabling the Reading Pane prevents malicious S/MIME certificates from being processed in Outlook 2007. While this prevents malicious certificates from being processed in Outlook, it does not prevent a local, authenticated user from running a specially crafted program to exploit this vulnerability. Opening an affected email message could still cause the malicious certificate to be loaded and processed.

    To disable the Reading Pane in Outlook 2007, see Turn the Reading Pane on or off.

  • Disable the Reading Pane in Outlook 2010

    Disabling the Reading Pane prevents malicious S/MIME certificates from being processed in Outlook 2010. While this prevents malicious certificates from being processed in Outlook, it does not prevent a local, authenticated user from running a specially crafted program to exploit this vulnerability. Opening an affected email message could still cause the malicious certificate to be loaded and processed.

    To disable the Reading Pane in Outlook 2010, see Turn on or off the Reading Pane.

FAQ

What is the scope of the vulnerability? 
This is a remote code execution vulnerability.

What causes the vulnerability? 
The vulnerability is caused when Microsoft Outlook fails to properly parse the contents of an S/MIME message.

What is S/MIME?
S/MIME stands for Secure/Multipurpose Internet Mail Extensions. S/MIME provides a consistent way to send and receive MIME encoded data securely. Based on the popular Internet MIME standard, S/MIME provides the following cryptographic security services for electronic messaging applications: authentication, message integrity and non-repudiation of origin (using digital signatures), and privacy and data security (using encryption). For more information, see Understanding S/MIME.

What might an attacker use the vulnerability to do? 
An attacker who successfully exploited this vulnerability could run arbitrary code as the logged-on user. If a user is logged on with administrative user rights, an attacker could take complete control of the 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 impacted than users who operate with administrative user rights.

How could an attacker exploit the vulnerability? 
In an email attack scenario, an attacker could exploit the vulnerability by sending a specially crafted email message to the user and then convincing the user to preview or open the email.

Exploitation of this vulnerability requires that a user open or preview a specially crafted email message with an affected version of Microsoft Outlook

What systems are primarily at risk from the vulnerability? 
Systems such as workstations and terminal servers where Microsoft Outlook is used at risk. Servers could be at more risk if administrators allow users to log on to servers and to run programs. However, best practices strongly discourage allowing this.

What does the update do? 
The update addresses the vulnerability by correcting the way that Microsoft Outlook parses specially crafted S/MIME email messages.

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.

Update Information

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 more information about these tools and guidance in deploying security updates across networks, see Security Tools for IT Pros

Security Update Deployment

Affected Software

For information about the specific security update for your affected software, click the appropriate link:

Microsoft Outlook 2007 (all editions)

Reference Table

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

Security update file name For Microsoft Outlook 2007:\ outlook2007-kb2825999-fullfile-x86-glb.exe
Installation switches See Microsoft Knowledge Base Article 912203
Restart requirement In some cases, this update does not require a restart. If the required files are being used, this update will require a restart. If this behavior occurs, a message appears that advises you to restart.\ \ To help reduce the chance that a restart will be required, stop all affected services and close all applications that may use the affected files prior to installing the security update. For more information about the reasons why you may be prompted to restart, see Microsoft Knowledge Base Article 887012.
Removal information Use Add or Remove Programs item in Control Panel.
File information See Microsoft Knowledge Base Article 2825999
Registry key verification Not applicable

Microsoft Outlook 2010 (all editions)

Reference Table

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

Security update file name For Microsoft Outlook 2010 (32-bit editions):\ outlook2010-kb2794707-fullfile-x86-glb.exe
For Microsoft Outlook 2010 (64-bit editions):\ outlook2010-kb2794707-fullfile-x64-glb.exe
Installation switches See Microsoft Knowledge Base Article 912203
Restart requirement In some cases, this update does not require a restart. If the required files are being used, this update will require a restart. If this behavior occurs, a message appears that advises you to restart.\ \ To help reduce the chance that a restart will be required, stop all affected services and close all applications that may use the affected files prior to installing the security update. For more information about the reasons why you may be prompted to restart, see Microsoft Knowledge Base Article 887012.
Removal information Use Add or Remove Programs item in Control Panel.
File information See Microsoft Knowledge Base Article 2794707
Registry key verification Not applicable

Other Information

Acknowledgments

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

  • Alexander Klink of n.runs AG for reporting the Message Certificate Vulnerability (CVE-2013-3870)

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

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 (September 10, 2013): Bulletin published.
  • V1.1 (September 10, 2013): Added workarounds in the Vulnerability Information section that explain how to disable the Reading Pane in Outlook 2007 and Outlook 2010.

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