SecurityvulnsSECURITYVULNS:DOC:24740Microsoft Security Bulletin MS10-061 - Critical Vulnerability in Print Spooler Service Could Allow Remote Code Execution (2347290)
Microsoft Security Bulletin MS10-061 - Critical
Vulnerability in Print Spooler Service Could Allow Remote Code Execution (2347290)
Published: September 14, 2010
Version: 1.0
General Information
Executive Summary
This security update resolves a publicly disclosed vulnerability in the Print Spooler service. The vulnerability could allow remote code execution if an attacker sends a specially crafted print request to a vulnerable system that has a print spooler interface exposed over RPC. By default, printers are not shared on any currently supported Windows operating system.
This security update is rated Critical for all supported editions of Windows XP, and Important for all supported editions of Windows Server 2003, Windows Vista, Windows Server 2008, Windows 7, and 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 Printer Spooler service validates user permissions. 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 immediately 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. None
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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 XP Service Pack 3
Remote Code Execution
Critical
None
Windows XP Professional x64 Edition Service Pack 2
Remote Code Execution
Critical
None
Windows Server 2003 Service Pack 2
Elevation of Privilege
Important
None
Windows Server 2003 x64 Edition Service Pack 2
Elevation of Privilege
Important
None
Windows Server 2003 with SP2 for Itanium-based Systems
Elevation of Privilege
Important
None
Windows Vista Service Pack 1 and Windows Vista Service Pack 2
Elevation of Privilege
Important
None
Windows Vista x64 Edition Service Pack 1 and Windows Vista x64 Edition Service Pack 2
Elevation of Privilege
Important
None
Windows Server 2008 for 32-bit Systems and Windows Server 2008 for 32-bit Systems Service Pack 2*
Elevation of Privilege
Important
None
Windows Server 2008 for x64-based Systems and Windows Server 2008 for x64-based Systems Service Pack 2*
Elevation of Privilege
Important
None
Windows Server 2008 for Itanium-based Systems and Windows Server 2008 for Itanium-based Systems Service Pack 2
Elevation of Privilege
Important
None
Windows 7 for 32-bit Systems
Elevation of Privilege
Important
None
Windows 7 for x64-based Systems
Elevation of Privilege
Important
None
Windows Server 2008 R2 for x64-based Systems*
Elevation of Privilege
Important
None
Windows Server 2008 R2 for Itanium-based Systems
Elevation of Privilege
Important
None
*Server Core installation affected. This update applies, with the same severity rating, to supported editions of Windows Server 2008 or Windows Server 2008 R2 as indicated, whether or not 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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Frequently Asked Questions (FAQ) Related to This Security Update
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.
Why is this vulnerability rated as a higher severity on Windows XP systems?
On Windows XP, the guest account is enabled by default, which allows anonymous users to access printer shares. On Windows Server 2003, Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2, an attacker must be authenticated in order to exploit this vulnerability unless password-based sharing is disabled. If password-based sharing is disabled, attackers could exploit these systems without authentication.
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 September bulletin summary. For more information, see Microsoft Exploitability Index.
Vulnerability Severity Rating and Maximum Security Impact by Affected Software
Affected Software Print Spooler Service Impersonation Vulnerability - CVE-2010-2729 Aggregate Severity Rating
Windows XP Service Pack 3
Critical
Remote Code Execution
Critical
Windows XP Professional x64 Edition Service Pack 2
Critical
Remote Code Execution
Critical
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 Service Pack 1 and Windows Vista Service Pack 2
Important
Elevation of Privilege
Important
Windows Vista x64 Edition Service Pack 1 and Windows Vista x64 Edition Service Pack 2
Important
Elevation of Privilege
Important
Windows Server 2008 for 32-bit Systems and Windows Server 2008 for 32-bit Systems Service Pack 2*
Important
Elevation of Privilege
Important
Windows Server 2008 for x64-based Systems and Windows Server 2008 for x64-based Systems Service Pack 2*
Important
Elevation of Privilege
Important
Windows Server 2008 for Itanium-based Systems and Windows Server 2008 for Itanium-based Systems Service Pack 2
Important
Elevation of Privilege
Important
Windows 7 for 32-bit Systems
Important
Elevation of Privilege
Important
Windows 7 for x64-based Systems
Important
Elevation of Privilege
Important
Windows Server 2008 R2 for x64-based Systems*
Important
Elevation of Privilege
Important
Windows Server 2008 R2 for Itanium-based Systems
Important
Elevation of Privilege
Important
*Server Core installation affected. This update applies, with the same severity rating, to supported editions of Windows Server 2008 or Windows Server 2008 R2 as indicated, whether or not 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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Print Spooler Service Impersonation Vulnerability - CVE-2010-2729
A remote code execution vulnerability exists in the Windows Print Spooler service that could allow a remote, unauthenticated attacker to execute arbitrary code on an affected Windows XP system. 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. This is an elevation of privilege vulnerability on all other supported Microsoft Windows systems.
To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2010-2729.
Mitigating Factors for Print Spooler Service Impersonation Vulnerability - CVE-2010-2729
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:
•
By default, printers are not shared on any of the currently supported Windows operating systems.
•
Systems are only vulnerable to remote attack when sharing a printer and the remote attacker can access the printer share.
•
Firewall best practices and standard default firewall configurations can help protect networks from attacks that originate outside the enterprise perimeter. Best practices recommend that systems that are connected to the Internet have a minimal number of ports exposed.
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Workarounds for Print Spooler Service Impersonation Vulnerability - CVE-2010-2729
Workaround refers to a setting or configuration change that does not correct the underlying vulnerability but would help block known attack vectors before you apply the update. Microsoft has tested the following workarounds and states in the discussion whether a workaround reduces functionality:
•
Block ports associated with RPC at the firewall
•
UDP ports 135, 137, 138, and 445, and TCP ports 135, 139, 445, and 593
•
All unsolicited inbound traffic on ports greater than 1024
•
Any other specifically configured RPC port
These ports are used to initiate a connection with RPC. Blocking them at the firewall will help protect systems that are behind that firewall from attempts to exploit this vulnerability. Also, make sure that you block any other specifically configured RPC port on the remote system. Microsoft recommends that you block all unsolicited inbound communication from the Internet to help prevent attacks that may use other ports. For more information about ports, see the TechNet article, TCP and UDP Port Assignments.
Impact of workaround. Several Windows services use the affected ports. Blocking connectivity to the ports may cause various applications or services to not function. Some of the applications or services that could be impacted are listed below:
•
Applications that use SMB (CIFS)
•
Applications that use mailslots or named pipes (RPC over SMB)
•
Server (File and Print Sharing)
•
Group Policy
•
Net Logon
•
Distributed File System (DFS)
•
Terminal Server Licensing
•
Print Spooler
•
Computer Browser
•
Remote Procedure Call Locator
•
Fax Service
•
Indexing Service
•
Performance Logs and Alerts
•
Systems Management Server
•
License Logging Service
How to undo the workaround. Unblock UDP ports 135, 137, 138, and 445, and TCP ports 135, 139, 445, and 593 at the firewall. For more information about ports, see TCP and UDP Port Assignments.
•
Disable printer sharing
To disable printer sharing, perform the following actions:
On Windows XP and Windows 2003 systems
Click Start, and then click Printer and Faxes.
Right-click the printer icon and select Sharing.
Select Do Not Share This Printer, and then click OK.
Repeat this process for each printer shared on the system.
On all later Windows operating systems:
Click Start, and then click Devices and Printers.
Right-click the printer icon and select Printer properties.
Select the Sharing tab.
Ensure the Share this printer option is not selected, and then click OK.
Repeat this process for each printer shared on the system.
Impact of workaround. By disabling this feature, remote users will not be able to print to the affected printer.
How to undo the workaround:
On Windows XP and Windows 2003 systems:
Click Start, and then click Printer and Faxes.
Right-click the printer icon and select Sharing.
Select Share This Printer, and then click OK.
Repeat this process for each printer shared on the system.
On all later Windows operating systems:
Click Start, and then click Devices and Printers.
Right-click the printer icon and select Printer properties.
Select the Sharing tab.
Select the Share this printer option, and then click OK.
Repeat this process for each printer shared on the system.
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FAQ for Print Spooler Service Impersonation Vulnerability - CVE-2010-2729
What is the scope of the vulnerability?
This is a remote code execution vulnerability. 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.
What causes the vulnerability?
This vulnerability is caused when the Windows Print Spooler insufficiently restricts user permissions to access print spoolers.
What is the Print Spooler service?
The Print Spooler service is an executable file that is installed as a service. The spooler is loaded when the operating system starts, and it continues to run until the operating system is shut down. The Print Spooler service manages the printing process, which includes such tasks as retrieving the location of the correct printer driver, loading that driver, spooling high-level function calls into a print job, and scheduling print jobs. When the tasks for a particular print job are complete, the Print Spooler service passes the job to the print router. For more information, see the TechNet article, How Network Printing Works.
What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could run arbitrary code on a user's system with system privileges. 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.
How could an attacker exploit the vulnerability?
An attacker could exploit this vulnerability by crafting and sending a malicious print request to a vulnerable system that has a print spooler interface exposed over RPC. The target system would not properly validate whether the remote user has sufficient permissions, and permit the remote attacker to create a file in a Windows system directory. When dropped in particular locations, these files may be automatically executed by the system.
What systems are primarily at risk from the vulnerability?
Workstations and terminal servers that share a printer, or print 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 manner in which the Printer Spooler service validates user permissions to access print spoolers.
When this security bulletin was issued, had this vulnerability been publicly disclosed?
Yes. This vulnerability has been publicly disclosed. It has been assigned Common Vulnerability and Exposure number CVE-2010-2729.
When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
Yes. At the time this bulletin was released, this vulnerability was being exploited on a limited scale by malware.
Other Information
Acknowledgments
Microsoft thanks the following for working with us to help protect customers:
•
Sergey Golovanov, Alexander Gostev, Maxim Golovkin, and Alexey Monastyrsky of Kaspersky Lab, and Vitaly Kiktenko and Alexander Saprykin of Design and Test Lab for reporting the Print Spooler Service Impersonation Vulnerability (CVE-2010-2729)
•
Liam O Morchu of Symantec for reporting the Print Spooler Service Impersonation Vulnerability (CVE-2010-2729)
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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.
Support
•
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.
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
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V1.0 (September 14, 2010): Bulletin published.
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