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Microsoft Security Bulletin MS13-041 - Important

Vulnerability in Lync Could Allow Remote Code Execution (2834695)

Published: May 14, 2013

Version: 1.0

General Information

Executive Summary

This security update resolves a privately reported vulnerability in Microsoft Lync. The vulnerability could allow remote code execution if an attacker shares specially crafted content, such as a file or program, as a presentation in Lync or Communicator and then convinces a user to accept an invitation to view or share the presentable content. In all cases, an attacker would have no way to force users to view or share the attacker-controlled file or program. Instead, an attacker would have to convince users to take action, typically by getting them to accept an invitation in Lync or Communicator to view or share the presentable content.

This security update is rated Important for supported editions of Microsoft Communicator 2007 R2, Microsoft Lync 2010, Microsoft Lync 2010 Attendee, and Microsoft Lync Server 2013. For more information, see the subsection, Affected and Non-Affected Software, in this section.

The security update addresses the vulnerability by modifying the way that the Lync and Communicator clients handle objects in memory. For more information about the vulnerability, see the Frequently Asked Questions (FAQ) subsection 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 in supported editions of Windows XP and Windows Server 2003, see Microsoft Knowledge Base Article 294871. For information about automatic updating in supported editions of Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2, see Understanding Windows automatic updating.

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 2834695
File informationYes
SHA1/SHA2 hashesYes
Known issuesYes

Affected and Non-Affected Software

The following software have 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 Communications Platforms and Software 

SoftwareMaximum Security ImpactAggregate Severity RatingUpdates Replaced
Microsoft Communicator 2007 R2
(2827753)
Remote Code ExecutionImportant2726391 in MS12-066
Microsoft Lync 2010 (32-bit)
(2827750)
Remote Code ExecutionImportant2726382 in MS12-066
Microsoft Lync 2010 (64-bit)
(2827750)
Remote Code ExecutionImportant2726382 in MS12-066
Microsoft Lync 2010 Attendee
(admin level install)
(2827752)
Remote Code ExecutionImportant2726388 in MS12-066
Microsoft Lync 2010 Attendee [1]
(user level install)
(2827751)
Remote Code ExecutionImportant2726384 in MS12-066
Microsoft Lync Server 2013 [ 2 ]
(Web Components Server)
(2827754)
Remote Code ExecutionImportantNone

[1]This update is available from the Microsoft Download Center only. See the Update FAQ section for more information.

[ 2 ]Applying the Lync Server 2013 security update (2827754) also installs the February 2013 cumulative updates for Lync Server 2013.

Non-Affected Software 

Office and Other Software
Microsoft Communicator 2005
Microsoft Communicator 2005 Web Access
Microsoft Communicator 2007
Microsoft Communicator 2007 Web Access
Microsoft Communications Server 2007
Microsoft Communications Server 2007 Speech Server
Microsoft Communications Server 2007 R2
Microsoft Communicator 2007 R2 Attendant
Microsoft Communicator 2007 R2 Group Chat Admin
Microsoft Communicator 2007 R2 Group Chat Client
Microsoft Live Meeting 2007 Console
Microsoft Communicator for Mac 2011
Microsoft Communicator Mobile
Microsoft Communicator Phone Edition
Microsoft Lync Server 2010
Microsoft Lync 2010 Attendant (32-bit)
Microsoft Lync 2010 Attendant (64-bit)
Microsoft Lync 2010 Group Chat
Microsoft Lync Server 2010 Group Chat Software Development Kit
Microsoft Lync for Mac 2011
Microsoft Lync 2013 (32-bit)
Microsoft Lync 2013 (64-bit)

Why is the Lync 2010 Attendee (user level install) update only available from the Microsoft Download Center? 
Microsoft is releasing the update for Lync 2010 Attendee (user level install) to the Microsoft Download Center only. Because the user level installation of Lync 2010 Attendee is handled through a Lync session, distribution methods such as automatic updating are not appropriate for this type of installation scenario.

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 have 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

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

Vulnerability Severity Rating and Maximum Security Impact by Affected Software
Affected SoftwareLync RCE Vulnerability - CVE-2013-1302Aggregate Severity Rating
Microsoft Communications Platforms and Software 
Microsoft Communicator 2007 R2 Important
Remote Code Execution
Important
Microsoft Lync 2010 (32-bit) Important
Remote Code Execution
Important
Microsoft Lync 2010 (64-bit) Important
Remote Code Execution
Important
Microsoft Lync 2010 Attendee (admin level install) Important
Remote Code Execution
Important
Microsoft Lync 2010 Attendee (user level install) Important
Remote Code Execution
Important
Microsoft Lync Server 2013
(Web Components Server)
Important
Remote Code Execution
Important

A remote code execution vulnerability exists when the Lync control attempts to access an object in memory that has been deleted. An attacker could exploit the vulnerability by convincing a target user to accept an invitation to launch specially crafted content within a Lync or Communicator session. An attacker who successfully exploited this vulnerability could gain the same user rights as the current user.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2013-1302.

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 all cases, an attacker would have no way to force users to view or share the attacker-controlled file or program. Instead, an attacker would have to convince users to take action, typically by getting them to accept an invitation in Lync or Communicator to view or share the presentable content.
  • 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

Microsoft has not identified any workarounds for this vulnerability.

FAQ

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

What causes the vulnerability? 
When Microsoft Lync attempts to access an object in memory that has been deleted, it may corrupt memory in such a way that an attacker could execute arbitrary code in the context of the current user.

Does EMET help mitigate attacks that could attempt to exploit th is vulnerability ? 
Yes. The Enhanced Mitigation Experience Toolkit (EMET) enables users to manage security mitigation technologies that help make it more difficult for attackers to exploit vulnerabilities in a given piece of software. EMET helps to mitigate this vulnerability in Lync and Communicator on systems where EMET is installed and configured to work with these applications.

For more information about EMET, see The Enhanced Mitigation Experience Toolkit.

What might an attacker use the vulnerability to do? 
An attacker who successfully exploited this vulnerability could gain the same user rights as the current user. If the current 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.

How could an attacker exploit the vulnerability? 
An attacker could share specially crafted content, such as a file or a program, as a presentation in a Lync or Communicator session and then convince a user to view or share the specially crafted content. In all cases, an attacker would have no way to force users to view or share the attacker-controlled file or program. Instead, an attacker would have to convince users to take action, typically by getting them to accept an invitation in Lync or Communicator to view or share the presentable content.

What systems are primarily at risk from the vulnerability? 
Systems with affected editions Lync or Communicator installed are at risk from this vulnerability.

What does the update do? 
The update addresses the vulnerability by modifying the way that the Lync and Communicator clients handle objects in memory.

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

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 (SCCM) 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

Affected Software

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

Microsoft Communicator 2007 R2, Microsoft Lync 2010, Microsoft Lync 2010 Attendee, Microsoft Lync Server 2013

Reference Table

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

Security update file name For Microsoft Communicator 2007 R2 (2827753):
communicator.msp
 For Microsoft Lync 2010 (32-bit) (2827750):
lync.msp
For Microsoft Lync 2010 (64-bit) (2827750):
lync.msp
For Microsoft Lync 2010 Attendee (admin level install) (2827752):
AttendeeAdmin.msp
For Microsoft Lync 2010 Attendee (user level install) (2827751):
AttendeeUser.msp
For Microsoft Lync Server 2013 (Web Components Server) (2827754) and February 2013 cumulative updates for Lync Server 2013:
WebComponents.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.

Note The update for Microsoft Lync Web Access 2013 does not require a restart.
Removal Information Use Add or Remove Programs item in Control Panel.
File Information For Microsoft Communicator 2007 R2:
See Microsoft Knowledge Base Article 2827753
For all supported editions of Microsoft Lync 2010:
See Microsoft Knowledge Base Article 2827752
For Microsoft Lync 2010 Attendee (admin level install):
See Microsoft Knowledge Base Article 2827752
For Microsoft Lync 2010 Attendee (user level install):
See Microsoft Knowledge Base Article 2827751
For Microsoft Lync Server 2013 (Web Components Server):
See Microsoft Knowledge Base Article 2827754
Registry Key Verification For Microsoft Communicator 2007 R2 :
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{0EEB34F6-991D-4a1b-8EEB-772DA0EADB22}
Version = 6907.268
For Microsoft Lync 2010 (32-bit):
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{0EEB34F6-991D-4a1b-8EEB-772DA0EADB22}
Version = 7577.4388
For Microsoft Lync 2010 (64-bit):
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Active Setup\Installed Components\{0EEB34F6-991D-4a1b-8EEB-772DA0EADB22}
Version = 7577.4388
For Microsoft Lync 2010 Attendee (admin level install):
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UserData\S-1-5-18\Products\DB2129A1633F81B43ADD0A24A11A1895\InstallProperties
DisplayVersion = 4.0.7577.4388
For Microsoft Lync 2010 Attendee (user level install):
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Active Setup\Installed Components\{0EEB34F6-991D-4a1b-8EEB-772DA0EADB22}\
Version = 7577.4388
For Microsoft Lync Server 2013 (Web Components Server):
HKEY_LOCAL_MACHINE\Software\Microsoft\Real-Time Communications\{2A65AB9C-57AD-4EC6-BD4E-BD61A7C583B3}\Version}
Version = 8308.315

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

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 (May 14, 2013): Bulletin published.

Built at 2014-04-18T13:49:36Z-07:00

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