Microsoft Security Bulletin MS11-061 - Important
Vulnerability in Remote Desktop Web Access Could Allow Elevation of Privilege (2546250)
Published: August 09, 2011
This security update resolves a privately reported vulnerability in Remote Desktop Web Access. The vulnerability is a cross-site scripting (XSS) vulnerability that could allow elevation of privilege, enabling an attacker to execute arbitrary commands on the site in the context of the target user. The XSS Filter in Internet Explorer 8 and Internet Explorer 9 prevents this attack for its users when browsing to a Remote Desktop Web Access server in the Internet Zone. The XSS Filter in Internet Explorer 8 and Internet Explorer 9 is not enabled by default in the Intranet Zone.
This security update is rated Important for all supported editions of Windows Server 2008 R2. For more information, see the subsection, Affected and Non-Affected Software, in this section.
The security update addresses the vulnerability by correcting the manner in which the logon page for Remote Desktop Web Access validates input parameters. For more information about the vulnerability, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability entry under the next section, Vulnerability Information.
Recommendation. The majority of 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.
Known Issues. Microsoft Knowledge Base Article 2546250 documents the currently known issues that customers may experience when installing this security update. The article also documents recommended solutions for these issues.
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, visit Microsoft Support Lifecycle.
|Operating System||Maximum Security Impact||Aggregate Severity Rating||Bulletins Replaced by this Update|
|Windows Server 2008 R2 for x64-based Systems and Windows Server 2008 R2 for x64-based Systems Service Pack 1**||Elevation of Privilege||Important||None|
**Server Core installation not affected. The vulnerabilities addressed by this update do not affect supported editions of Windows Server 2008 or Windows Server 2008 R2 as indicated, when installed using the Server Core installation option. For more information on this installation option, see the TechNet articles, Managing a Server Core Installation and Servicing a Server Core Installation. Note that the Server Core installation option does not apply to certain editions of Windows Server 2008 and Windows Server 2008 R2; see Compare Server Core Installation Options.
|Windows XP Service Pack 3|
|Windows XP Professional x64 Edition Service Pack 2|
|Windows Server 2003 Service Pack 2|
|Windows Server 2003 x64 Edition Service Pack 2|
|Windows Server 2003 with SP2 for Itanium-based Systems|
|Windows Vista Service Pack 2|
|Windows Vista x64 Edition Service Pack 2|
|Windows Server 2008 for 32-bit Systems Service Pack 2|
|Windows Server 2008 for x64-based Systems Service Pack 2|
|Windows Server 2008 for Itanium-based Systems Service Pack 2|
|Windows 7 for 32-bit Systems and Windows 7 for 32-bit Systems Service Pack 1|
|Windows 7 for x64-based Systems and Windows 7 for x64-based Systems Service Pack 1|
|Windows Server 2008 R2 for Itanium-based Systems and Windows Server 2008 R2 for Itanium-based Systems Service Pack 1|
Frequently Asked Questions (FAQ) Related to This Security Update
I have customized my web enrollment ASP pages. Do I need to be concerned with the known issues listed in Microsoft Knowledge Base Article 2546250?
Yes, Microsoft recommends that customers who have edited their Web enrollment ASP pages should visit Microsoft Knowledge Base Article 2546250 for important information about known issues that may apply to their systems.
Where are the file information details?
Refer to the reference tables in the Security Update Deployment section for the location of the file information details.
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, visit the Microsoft Support Lifecycle Web site.
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 Lifecycle Supported Service Packs.
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, visit the Microsoft Worldwide Information Web site, 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 August bulletin summary. For more information, see Microsoft Exploitability Index.
|Affected Software||Remote Desktop Web Access Vulnerability - CVE-2011-1263||Aggregate Severity Rating|
|Windows Server 2008 R2 for x64-based Systems and Windows Server 2008 R2 for x64-based Systems Service Pack 1**||Important
Elevation of Privilege
|Inclusion in Future Service Packs||The update for this issue will be included in a future service pack or update rollup|
|Installing without user intervention||For all supported x64-based editions of Windows Server 2008 R2:
|Installing without restarting||For all supported x64-based editions of Windows Server 2008 R2:
Windows6.1-KB2546250-x64.msu /quiet /norestart
|Further information||See the subsection, Detection and Deployment Tools and Guidance|
|Restart required?||This update does not require a restart. The installer stops the required services, applies the update, and then restarts the services. However, if the required services cannot be stopped for any reason, or if required files are being used, this update will require a restart. If this behavior occurs, a message appears that advises you to restart.|
|Removal Information||This security update cannot be deleted.|
|File Information||See Microsoft Knowledge Base Article 2546250|
|Registry Key Verification||Note A registry key does not exist to validate the presence of this update.|
Supported Security Update Installation Switches
|/?, /h, /help||Displays help on supported switches.|
|/quiet||Suppresses the display of status or error messages.|
|/norestart||When combined with /quiet, the system will not be restarted after installation even if a restart is required to complete installation.|
|/warnrestart:<seconds>||When combined with /quiet, the installer will warn the user before initiating restart.|
|/promptrestart||When combined with /quiet, the installer will prompt before initiating restart.|
|/forcerestart||When combined with /quiet, the installer will forcefully close applications and initiate restart.|
|/log:<file name>||Enables logging to specified file.|
|/extract:<destination>||Extracts the package contents to the destination folder.|
|/uninstall /kb:<KB Number>||Uninstalls the security update.|
Note For more information about the wusa.exe installer, see "Windows Update Stand-alone Installer" in the TechNet article, Miscellaneous Changes in Windows 7.
Verifying That the Update Has Been Applied
Microsoft Baseline Security Analyzer
To verify that a security update has been applied to an affected system, you may be able to use the Microsoft Baseline Security Analyzer (MBSA) tool. See the section, Detection and Deployment Tools and Guidance, earlier in this bulletin for more information.
File Version Verification
Because there are several editions of Microsoft Windows, the following steps may be different on your system. If they are, see your product documentation to complete these steps.
- Click Start and then enter an update file name in the Start Search box.
- When the file appears under Programs, right-click the file name and click Properties.
- On the General tab, compare the file size with the file information tables provided in the bulletin KB article.
Note Depending on the edition of the operating system, or the programs that are installed on your system, some of the files that are listed in the file information table may not be installed.
- You can also click the Details tab and compare information, such as file version and date modified, with the file information tables provided in the bulletin KB article.
Note Attributes other than the file version may change during installation. Comparing other file attributes to the information in the file information table is not a supported method of verifying that the update has been applied. Also, in certain cases, files may be renamed during installation. If the file or version information is not present, use one of the other available methods to verify update installation.
- Finally, you can also click the Previous Versions tab and compare file information for the previous version of the file with the file information for the new, or updated, version of the file.
Microsoft thanks the following for working with us to help protect customers:
- Sven Taute for reporting the Remote Desktop Web Access Vulnerability (CVE-2011-1263)
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 visit the active protections Web sites provided by program partners, listed in Microsoft Active Protections Program (MAPP) Partners.
- Customers in the U.S. and Canada can receive technical support from Security Support or 1-866-PCSAFETY. There is no charge for support calls that are associated with security updates. For more information about available support options, see Microsoft Help and Support.
- International customers can receive support from their local Microsoft subsidiaries. There is no charge for support that is associated with security updates. For more information about how to contact Microsoft for support issues, visit the International Support Web site.
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.
- V1.0 (August 9, 2011): Bulletin published.
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