MS13-094: Description of the security update for Outlook 2013: November 12, 2013

Outlook 2013


This update resolves a security vulnerability in Microsoft Outlook that could allow information disclosure when a specially crafted email message is opened or previewed.


Microsoft has released security bulletin MS13-094. To view the complete security bulletin, go to one of the following Microsoft websites:

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

More information about this security update

Download information

This update is available for download from the Microsoft Download Center:

Known issues with this security update

After you install this security update, you may experience the following issues:
  • Outlook crashes shortly after the program starts.
  • If you are using Outlook to connect to an IMAP email account, you may not receive new email messages. Or, you may receive an error message that resembles either of the following when you move or delete an email message:

    You do not have appropriate permission to perform this operation.
    You do not have permission to move items in this folder.
  • If you are using Outlook to connect to a Microsoft Exchange Server 2007 mailbox:
    • You receive an error message that resembles either of the following when you try to configure Automatic Replies (Out of Office):

      Your automatic reply settings cannot be displayed because the server is currently unavailable. Try again later.
    • You cannot retrieve Free/Busy data for calendar scheduling.
    • Add-ins that use the Account.SmtpAddress property no longer work.
    These features rely on an underlying Autodiscover technology. After you install this security update, Autodiscover may fail for Exchange 2007 configurations. Therefore, Outlook features that rely on Autodiscover will also stop working.

    To resolve these issues, install update 2850061.

    The following files are available for download from the Microsoft Download Center:

    For supported x86-based systems

    Download Download the outlookloc2013-kb2850061-fullfile-x86-glb.exe package now.

    For supported x64-based systems

    Download Download the outlookloc2013-kb2850061-fullfile-x64-glb.exe package now.

    Release Date: December 13, 2013

    For more information about how to download Microsoft support files, click the following article number to view the article in the Microsoft Knowledge Base:
    119591 How to obtain Microsoft support files from online services
    Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help prevent any unauthorized changes to the file.
  • After this update is applied, you may experience issues with S/MIME certificate verification in Microsoft Outlook. This issue occurs because the update disables remote intermediate certificate fetching in Outlook.

    If you experience these issues, or if you are working in an enterprise installation that requires the retrieval of remote certificates referenced in an authority information access extension, a registry key can be set to enable remote intermediate certificate fetching in Outlook.

    Warning Setting the registry key to enable remote intermediate certificate fetching removes the protections provided by this update.

    Important Follow the steps in this section carefully. Serious problems might occur if you modify the registry incorrectly. Before you modify it, back up the registry for restoration in case problems occur.

    To enable remote intermediate certificate fetching in Outlook after this update is applied, set the following registry key value:

    Registry location:
    hKEY_CURRENT_USER\Software\Policies\Microsoft\Office\15.0\Outlook\SecurityDWORD name: EnableAIACertExtension
    Value data: 1

    • You may have to create the Security subkey and the EnableAIACertExtension DWORD entry if they do not exist.
    • To disable the evaluation, set the Value data to 0 (0 is the default).

    Additionally, you can apply this registry key change across domains by using Group Policy. For more information about Group Policy, see Group Policy collection.

Prerequisites to apply this security update

To apply this security update, you must have Outlook 2013 installed on the computer.

Restart information

You may have to restart the computer after you install this security update.

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, you are prompted to restart the computer.

To reduce the possibility that a restart will be required, stop all affected services and exit all applications that may use the affected files before you install this security update.

For more information, see Why you may be prompted to restart your computer after you install a security update on a Windows-based computer.

Removal information

Note We do not recommend that you remove any security update.

To remove this security update, use the Add or Remove Programs item or the Programs and Features item in Control Panel.

Security update replacement information

This security update does not replace any previously released security update.