Security Bulletin
Microsoft Security Bulletin MS13-033 - Important
Vulnerability in Windows Client/Server Run-time Subsystem (CSRSS) Could Allow Elevation of Privilege (2820917)
Published: April 09, 2013
Version: 1.0
General Information
Executive Summary
This security update resolves a privately reported vulnerability in all supported editions of Windows XP, Windows Vista, Windows Server 2003, and Windows Server 2008. The vulnerability could allow elevation of privilege if an attacker logs on to a system and runs a specially crafted application. An attacker must have valid logon credentials and be able to log on locally to exploit this vulnerability.
This security update is rated Important for supported editions of Windows XP Professional x64 Edition and Windows Server 2003 and Moderate for supported editions of Windows XP, Windows Vista, and Windows Server 2008. 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 the Windows Client/Server Run-time Subsystem (CSRSS) handles objects in memory. 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. Most 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.
Knowledge Base Article
| Knowledge Base Article | 2820917 |
|---|---|
| File information | Yes |
| SHA1/SHA2 hashes | Yes |
| Known issues | None |
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
| Operating System | Maximum Security Impact | Aggregate Severity Rating | Updates Replaced |
|---|---|---|---|
| Windows XP | |||
| Windows XP Service Pack 3 (2820917) | Denial of Service | Moderate | 2646524 in MS12-003 |
| Windows XP Professional x64 Edition Service Pack 2 (2820917) | Elevation of Privilege | Important | 2646524 in MS12-003 |
| Windows Server 2003 | |||
| Windows Server 2003 Service Pack 2 (2820917) | Elevation of Privilege | Important | 2646524 in MS12-003 |
| Windows Server 2003 x64 Edition Service Pack 2 (2820917) | Elevation of Privilege | Important | 2646524 in MS12-003 |
| Windows Server 2003 with SP2 for Itanium-based Systems (2820917) | Elevation of Privilege | Important | 2646524 in MS12-003 |
| Windows Vista | |||
| Windows Vista Service Pack 2 (2820917) | Denial of Service | Moderate | 2646524 in MS12-003 |
| Windows Vista x64 Edition Service Pack 2 (2820917) | Denial of Service | Moderate | 2646524 in MS12-003 |
| Windows Server 2008 | |||
| Windows Server 2008 for 32-bit Systems Service Pack 2 (2820917) | Denial of Service | Moderate | 2646524 in MS12-003 |
| Windows Server 2008 for x64-based Systems Service Pack 2 (2820917) | Denial of Service | Moderate | 2646524 in MS12-003 |
| Windows Server 2008 for Itanium-based Systems Service Pack 2 (2820917) | Denial of Service | Moderate | 2646524 in MS12-003 |
| Server Core installation option | |||
| Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation) (2820917) | Denial of Service | Moderate | 2646524 in MS12-003 |
| Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation) (2820917) | Denial of Service | Moderate | 2646524 in MS12-003 |
Non-Affected Software
| Operating System |
|---|
| Windows 7 for 32-bit Systems |
| Windows 7 for 32-bit Systems Service Pack 1 |
| Windows 7 for x64-based Systems |
| Windows 7 for x64-based Systems Service Pack 1 |
| Windows Server 2008 R2 for x64-based Systems |
| Windows Server 2008 R2 for x64-based Systems Service Pack 1 |
| Windows Server 2008 R2 for Itanium-based Systems |
| Windows Server 2008 R2 for Itanium-based Systems Service Pack 1 |
| Windows 8 for 32-bit Systems |
| Windows 8 for 64-bit Systems |
| Windows Server 2012 |
| Windows RT |
| Server Core Installation Option |
| Windows Server 2008 R2 for x64-based Systems (Server Core installation) |
| Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) |
| Windows Server 2012 (Server Core installation) |
Update FAQ
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
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 April bulletin summary. For more information, see Microsoft Exploitability Index.
| Affected Software | CSRSS Memory Corruption Vulnerability - CVE-2013-1295 | Aggregate Severity Rating |
|---|---|---|
| Windows XP | ||
| Windows XP Service Pack 3 | Moderate Denial of Service | Moderate |
| Windows XP Professional x64 Edition Service Pack 2 | Important Elevation of Privilege | Important |
| Windows Sever 2003 | ||
| Windows Server 2003 Service Pack 2 | Important Elevation of Privilege | Important |
| Windows Server 2003 x64 Edition Service Pack 2 | Important Elevation of Privilege | Important |
| Windows Server 2003 with SP2 for Itanium-based Systems | Important Elevation of Privilege | Important |
| Windows Vista | ||
| Windows Vista Service Pack 2 | Moderate Denial of Service | Moderate |
| Windows Vista x64 Edition Service Pack 2 | Moderate Denial of Service | Moderate |
| Windows Server 2008 | ||
| Windows Server 2008 for 32-bit Systems Service Pack 2 | Moderate Denial of Service | Moderate |
| Windows Server 2008 for x64-based Systems Service Pack 2 | Moderate Denial of Service | Moderate |
| Windows Server 2008 for Itanium-based Systems Service Pack 2 | Moderate Denial of Service | Moderate |
| Server Core Installation Option | ||
| Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation) | Moderate Denial of Service | Moderate |
| Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation) | Moderate Denial of Service | Moderate |
CSRSS Memory Corruption Vulnerability - CVE-2013-1295
An elevation of privilege vulnerability exists when the Windows CSRSS improperly handles objects in memory. An attacker who successfully exploited this vulnerability could run arbitrary code in the context of the local 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-2013-1295.
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 must have valid logon credentials and be able to log on locally to exploit this vulnerability.
Workarounds
Microsoft has not identified any workarounds for this vulnerability.
FAQ
What is the scope of the vulnerability?
This is an elevation of privilege vulnerability.
What causes the vulnerability?
The vulnerability is caused when the Windows CSRSS improperly handles objects in memory.
What is the Windows Client/Server Runtime Subsystem (CSRSS)?
The Windows Client/Server Runtime Subsystem (CSRSS) is the user-mode portion of the Win32 subsystem (with Win32.sys being the kernel-mode portion). It is responsible for handling console windows, creating and/or deleting threads. It is an essential subsystem that must be running at all times.
What might an attacker use the vulnerability to do?
On Windows Server 2003, an attacker who successfully exploited this vulnerability could run arbitrary code in the context of the local system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.
On Windows XP, Windows Vista, and Windows Server 2008, an attacker who successfully exploited this vulnerability could cause the system to become unresponsive until restarted.
How could an attacker exploit the vulnerability?
To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability and take complete control over an affected system.
What systems are primarily at risk from the vulnerability?
Workstations and terminal servers are primarily 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 the Windows CSRSS handles 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
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 (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 information about these and other tools that are available, 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:
Windows XP (all editions)
Reference Table
The following table contains the security update information for this software.
| Security update file names | For Windows XP Service Pack 3:\ WindowsXP-KB2820917-x86-enu.exe |
|---|---|
| For Windows XP Professional x64 Edition Service Pack 2:\ WindowsServer2003.WindowsXP-KB2820917-x64-enu.exe | |
| Installation switches | See Microsoft Knowledge Base Article 262841 |
| Update log file | KB2820917.log |
| Restart requirement | Yes, you must restart your system after you apply this security update. |
| Removal information | Use Add or Remove Programs item in Control Panel or the Spuninst.exe utility located in the %Windir%$NTUninstallKB2820917$\Spuninst folder |
| File information | See Microsoft Knowledge Base Article 2820917 |
| Registry key verification | For all supported 32-bit editions of Windows XP:\ HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows XP\SP4\KB2820917\Filelist |
| For all supported x64-based editions of Windows XP:\ HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows XP Version 2003\SP3\KB2820917\Filelist |
Note The update for supported versions of Windows XP Professional x64 Edition also applies to supported versions of Windows Server 2003 x64 Edition.
Windows Server 2003 (all editions)
Reference Table
The following table contains the security update information for this software.
| Security update file names | For all supported 32-bit editions of Windows Server 2003:\ WindowsServer2003-KB2820917-x86-enu.exe |
|---|---|
| For all supported x64-based editions of Windows Server 2003:\ WindowsServer2003.WindowsXP-KB2820917-x64-enu.exe | |
| For all supported Itanium-based editions of Windows Server 2003:WindowsServer2003-KB2820917-ia64-enu.exe | |
| Installation switches | See Microsoft Knowledge Base Article 262841 |
| Update log file | KB2820917.log |
| Restart requirement | Yes, you must restart your system after you apply this security update. |
| Removal information | Use Add or Remove Programs item in Control Panel or the Spuninst.exe utility located in the %Windir%$NTUninstallKB2820917$\Spuninst folder |
| File information | See Microsoft Knowledge Base Article 2820917 |
| Registry key verification | HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows Server 2003\SP3\KB2820917\Filelist |
Note The update for supported versions of Windows Server 2003 x64 Edition also applies to supported versions of Windows XP Professional x64 Edition.
Windows Vista (all editions)
Reference Table
The following table contains the security update information for this software.
| Security update file names | For all supported 32-bit editions of Windows Vista:\ Windows6.0-KB2820917-x86.msu |
|---|---|
| For all supported x64-based editions of Windows Vista:\ Windows6.0-KB2820917-x64.msu | |
| Installation switches | See Microsoft Knowledge Base Article 934307 |
| Restart requirement | Yes, you must restart your system after you apply this security update. |
| Removal information | WUSA.exe does not support uninstall of updates. To uninstall an update installed by WUSA, click Control Panel, and then click Security. Under Windows Update, click View installed updates and select from the list of updates. |
| File information | See Microsoft Knowledge Base Article 2820917 |
| Registry key verification | Note A registry key does not exist to validate the presence of this update. |
Windows Server 2008 (all editions)
Reference Table
The following table contains the security update information for this software.
| Security update file names | For all supported 32-bit editions of Windows Server 2008:\ Windows6.0-KB2820917-x86.msu |
|---|---|
| For all supported x64-based editions of Windows Server 2008:\ Windows6.0-KB2820917-x64.msu | |
| For all supported Itanium-based editions of Windows Server 2008:\ Windows6.0-KB2820917-ia64.msu | |
| Installation switches | See Microsoft Knowledge Base Article 934307 |
| Restart requirement | Yes, you must restart your system after you apply this security update. |
| Removal information | WUSA.exe does not support uninstall of updates. To uninstall an update installed by WUSA, click Control Panel, and then click Security. Under Windows Update, click View installed updates and select from the list of updates. |
| File information | See Microsoft Knowledge Base Article 2820917 |
| Registry key verification | Note A registry key does not exist to validate the presence of this update. |
Other Information
Acknowledgments
Microsoft thanks the following for working with us to help protect customers:
- George Georgiev Valkov for reporting the CSRSS Memory Corruption Vulnerability (CVE-2013-1295)
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
- 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
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 (April 9, 2013): Bulletin published.
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