Otkriven je sigurnosni nedostatak vezan uz Remote Desktop Web Access kojeg udaljeni napadači mogu iskoristiti za umetanje proizvoljnog skriptnog koda, povećanje ovlasti i otkrivanje osjetljivih informacija.

Microsoft Security Bulletin MS11-061 - Important
Vulnerability in Remote Desktop Web Access Could Allow Elevation of Privilege (2546250)
Published: August 09, 2011

Version: 1.0
General Information
Executive Summary

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.
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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.

Affected Software
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.

Non-Affected Software
Operating System

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
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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.
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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 August bulletin summary. For more information, see Microsoft Exploitability Index.
Vulnerability Severity Rating and Maximum Security Impact by Affected Software
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
	

Important

**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.
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Remote Desktop Web Access Vulnerability - CVE-2011-1263

A reflected XSS vulnerability exists in Remote Desktop Web Access that could allow an attacker to inject a client-side script into the user's instance of Internet Explorer. This script could spoof content, disclose information, or take any action that the user could take on the Remote Desktop Web Access site.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2011-1263.
	
Mitigating Factors for Remote Desktop Web Access Vulnerability - CVE-2011-1263

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:
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