Microsoft Security Bulletin MS08-062 - Important Vulnerability in Windows Internet Printing Service Could Allow Remote Code Execution (953155)

Microsoft Security Bulletin MS08-062 - Important
Vulnerability in Windows Internet Printing Service Could Allow Remote Code Execution (953155)
Published: October 14, 2008

Version: 1.0
General Information
Executive Summary

This update resolves a privately reported vulnerability in the Windows Internet Printing Service that could allow remote code execution in the context of the current user. If a 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. 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.

This update is rated Important for all supported editions of Microsoft Windows 2000, Windows XP, Windows Server 2003, and Windows Server 2008. For more information, see the subsection, Affected and Non-Affected Software, in this section.

The security update addresses this vulnerability by changing the way that memory is allocated within the Internet Printing Protocol (IPP) service. 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. Microsoft recommends that customers apply the update at the earliest opportunity.

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

Microsoft Windows 2000 Service Pack 4

Remote Code Execution

Important

None

Windows XP Service Pack 2 and Windows XP Service Pack 3

Remote Code Execution

Important

None

Windows XP Professional x64 Edition and Windows XP Professional x64 Edition Service Pack 2

Remote Code Execution

Important

None

Windows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2

Remote Code Execution

Important

None

Windows Server 2003 x64 Edition and Windows Server 2003 x64 Edition Service Pack 2

Remote Code Execution

Important

None

Windows Server 2003 with SP1 for Itanium-based Systems and Windows Server 2003 with SP2 for Itanium-based Systems

Remote Code Execution

Important

None

Windows Vista and Windows Vista Service Pack 1

None

None

None

Windows Vista x64 Edition and Windows Vista x64 Edition Service Pack 1

None

None

None

Windows Server 2008 for 32-bit Systems*

Remote Code Execution

Important

None

Windows Server 2008 for x64-based Systems*

Remote Code Execution

Important

None

Windows Server 2008 for Itanium-based Systems

Remote Code Execution

Important

None

*Windows Server 2008 server core installation affected. For supported editions of Windows Server 2008, this update applies, with the same severity rating, whether or not Windows Server 2008 was installed using the Server Core installation option. For more information on this installation option, see Server Core. Note that the Server Core installation option does not apply to certain editions of Windows Server 2008; 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?
The file information details can be found in Microsoft Knowledge Base Article 953155.

Why is Microsoft Vista listed in the Affected Software table if it has no severity rating?
All supported editions of Windows Vista contain the shared print spooler component that is updated by this security update. However, because Internet Printing is not supported on Vista, the exploitable vector discussed in this security bulletin is not exposed. As a defense-in-depth measure to protect against any possible new vectors identified in the future, Windows Vista customers are encouraged to apply the security update.

Why is the update for Windows Vista only available on the download center?
A last-minute issue identified prior to release has delayed the posting of the security update for all supported editions of Windows Vista to Windows Update, Microsoft Update, Windows Software Update Services (WSUS), Systems Management Server, and System Center Configuration Manager. The security update is currently available through the Microsoft Download Center and will be released through the other distribution channels as soon as possible. This security bulletin will be updated to indicate when this security update is available through these other distribution channels.

I am running one of the platforms that are listed in the affected software table. Why am I not being offered the update?
The update will only be offered to systems on which the affected component is installed. Microsoft Windows 2000 and Windows XP systems that do not have IIS installed are not affected and will not receive this update. Windows Server 2003 and Windows Server 2008 systems that do not have both IIS and Internet printing installed are not affected and will not receive this update.

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. To determine the support life cycle for your software release, visit Microsoft Support Lifecycle.

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. For more information about the Windows Product Lifecycle, visit Microsoft Support Lifecycle. For more information about the extended security update support period for these software versions or editions, visit Microsoft Product Support Services.

Customers who require custom support for older releases 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 Microsoft Worldwide Information, select the country, 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 Windows Operating System Product Support Lifecycle FAQ.
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Vulnerability Information

Severity Ratings and Vulnerability Identifiers
Vulnerability Severity Rating and Maximum Security Impact by Affected Software
Affected Software Integer Overflow in IPP Service Vulnerability - CVE-2008-1446 Aggregate Severity Rating

Microsoft Windows 2000 Service Pack 4

Important
Remote Code Execution

Important

Windows XP Service Pack 2 and Windows XP Service Pack 3

Important
Remote Code Execution

Important

Windows XP Professional x64 Edition and Windows XP Professional x64 Edition Service Pack 2

Important
Remote Code Execution

Important

Windows Server 2003 Service Pack 1 and Windows Server 2003 Service Pack 2

Important
Remote Code Execution

Important

Windows Server 2003 x64 Edition and Windows Server 2003 x64 Edition Service Pack 2

Important
Remote Code Execution

Important

Windows Server 2003 with SP1 for Itanium-based Systems and Windows Server 2003 with SP2 for Itanium-based Systems

Important
Remote Code Execution

Important

Windows Vista and Windows Vista Service Pack 1

None

None

Windows Vista x64 Edition and Windows Vista x64 Edition Service Pack 1

None

None

Windows Server 2008 for 32-bit Systems*

Important
Remote Code Execution

Important

Windows Server 2008 for x64-based Systems*

Important
Remote Code Execution

Important

Windows Server 2008 for Itanium-based Systems

Important
Remote Code Execution

Important

*Windows Server 2008 server core installation affected. For supported editions of Windows Server 2008, this update applies, with the same severity rating, whether or not Windows Server 2008 was installed using the Server Core installation option. For more information on this installation option, see Server Core. Note that the Server Core installation option does not apply to certain editions of Windows Server 2008; see Compare Server Core Installation Options.
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Integer Overflow in IPP Service Vulnerability - CVE-2008-1446

A remote code execution vulnerability exists on Windows systems running IIS with the internet printing service enabled. This issue could allow a remote, authenticated attacker to execute arbitrary code on an affected system.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2008-1446.

Mitigating Factors for Integer Overflow in IPP Service Vulnerability - CVE-2008-1446

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:
•

Internet Printing Protocol (IPP) is enabled by default on IIS for Microsoft Windows 2000 and Windows XP. However, the default file permissions across all platforms are set so that IPP can only be accessed by users in the "Authenticated" group. Because of this restriction, unauthenticated users by default will not have the necessary folder permissions to exploit this vulnerability remotely.
•

Installations of IIS on Windows Server 2003 are not vulnerable in their default configuration. Only Windows Server 2003 installations that have enabled the Internet Printing Protocol ISAPI filter within IIS are vulnerable. Both the Internet Printing and Active Server Pages components are necessary to enable Web-based printer management and Internet printing. If Active Server Pages component is set to "Allowed" and Internet Printing component is set to "Prohibited," only Web-based printer management is enabled. Users cannot connect to any shared printers through Internet Printing.
•

Installations of IIS on Windows Server 2008 are not vulnerable by default. A computer running Windows Server 2008 can act as a client computer that uses Internet printing. Users of the computer who make print requests must be authenticated by the print server, however, before they can use any of the printers connected to that server. To enable a computer running Windows Server 2008 to act as a server supporting Internet printing, you must install the Web Server (IIS) role, the Print Services role, and the Internet Printing role service in the Print Services role.
•

Exploitation of this vulnerability requires that the IIS server communicate outbound to a malicious computer on port 445. Administrators who block outbound SMB connections from their IIS server to the Internet can prevent exploitation of this vulnerability from untrusted systems.
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Workarounds for Integer Overflow in IPP Service Vulnerability - CVE-2008-1446

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:
•

Disable the IPP Service

To disable IPP Service in IIS 5.0 and IIS 5.1

Open Internet Services Manager.

Right-click the Default Website and choose Properties.

Go to the Home Directory tab and select Configuration.

Scroll down to find the .printer extension and the corresponding path to msw3prt.dll.

Click Remove.

Click OK.

Restart the IIS Service.

Note Internet Printing can be configured via group policy as well as via the Internet Services Manager. If there is a conflict between the group policy settings and those in the Internet Service Manager, the group policy settings take precedence. If you remove Internet Printing via the Internet Services Manager, be sure to verify that it won’t be re-enabled by either local or domain group policies. (The default group policy neither enables nor disables Internet Printing.) In the MMC Group Policy snap-in, check Computer Configuration | Administrative Templates | Printing |Web-based Printing.

To disable IPP Service in IIS 6.0

Start IIS Manager or the IIS snap-in.

Expand * server_name, where server_name is the name of the server.

Click Web Service Extensions.

On the right pane, click Internet Printing, and then click Prohibited.

Quit IIS Manager.

To disable IPP Service in IIS 7.0 on Windows Server 2008

If ServerManager is not running, click Start, click Administrative Tools, and then click Server Manager. (If the User Account Control dialog box appears, confirm that the action it displays is what you want, and then click Continue.)

Expand the Roles node, and then right-click Print Services and select Remove Role Services.

The Remove Role Services wizard will appear. If the Internet Printing option is checked then clear the check box, click Next, and then Remove to complete the wizard.

Impact of workaround. Users will not be able to connect to any shared printers through Internet Printing.

How to undo the workaround.

To enable IPP Service in IIS 5.0 and IIS 5.1

Open Internet Services Manager.

Right-click the Default Website and choose Properties.

Go to the Home Directory tab and select Configuration.

Scroll down to find the .printer extension and the corresponding path to msw3prt.dll.

Click Add.

In the field marked Executable, input the following:
%systemroot%\system32\msw3prt.dll

In the field marked Extension, input the following:
.printer

In the field marked Limit to, input the following:
GET,POST

Once this is complete, restart the IIS service.

To enable IPP Service in IIS 6.0

Start IIS Manager or the IIS snap-in.

Expand * server_name, where server_name is the name of the server.

Click Web Service Extensions.

On the right pane, click Internet Printing, and then click Allow.

Quit IIS Manager.

To enable IPP Service in IIS 7.0

If ServerManager is not running, click Start, click Administrative Tools, and then click Server Manager. (If the User Account Control dialog box appears, confirm that the action it displays is what you want, and then click Continue.)

Expand the Roles node, and then right-click Print Services and select Add Role Services.

The Add Role Services wizard will appear. Check the Internet Printing option, click Next, and then Install to complete the wizard.
•

Run the IIS Lockdown Tool 2.1

On Microsoft Windows 2000 running IIS 5.0 or Windows XP running IIS 5.1, the IIS Lockdown Wizard version 2.1 can be used to disable unnecessary features, including Internet Printing. To run this wizard, complete the following actions:

Download the IIS Lockdown Tool 2.1 from here.

Do one of the following:

To start the installation immediately, click Open or Run this program from its current location.

To copy the download to your computer for installation at a later time, click Save or Save this program to disk.

Impact of Workaround.

Users will not be able to connect to any shared printers through Internet Printing. Additionally, the IIS Lockdown tool Users will not be able to connect to any shared printers through Internet Printing. For a complete list of changes made by the IIS Lockdown tool, see the following MSDN article.

How to undo the workaround.

To undo the changes made by IIS Lockdown, run IISlockd.exe a second time and choose to undo the changes. The undo operation restores the system settings that were in effect immediately before you previously ran IISLockdown. These details are contained in the log file \WINNT\System32\inetsrv\0blt-log. Therefore, it is important that you test the system promptly after you run IISLockdown. If an undo is required, perform it immediately.

Note The URLScan ISAPI filter that is installed as part of IIS Lockdown is not removed as part of the undo process. You can remove URLScan manually by using the ISAPI filters tab at the server level in Internet Services Manager.
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FAQ for Integer Overflow in IPP Service Vulnerability - CVE-2008-1446

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

What causes the vulnerability?
There exists a remote, authenticated vulnerability in the Microsoft Internet Printing Protocol (IPP) implementation on Windows servers running IIS. The IPP function is implemented as an ISAPI extension for IIS. An integer overflow exists in the IPP implementation that could allow an authenticated attacker to perform remote code execution on affected IIS servers.

What is ISAPI?
ISAPI (Internet Services Application Programming Interface) is a technology that enables web developers to extend the functionality of their web servers by writing custom code that provides new services for a web server. The custom code can either be implemented in an ISAPI filter, if the new functionality provides a low-level service, or an ISAPI extension, if the new functionality provides a high-level service. In this case, the affected code is an ISAPI extension.

What's the ISAPI extension at issue here?
The affected ISAPI extension is one that implements the Internet Printing Protocol (IPP), an industry standard defined in RFCs 2910 and 2911. IPP provides a way to request printing services and learn the status of print jobs across the Internet via HTTP. For instance, using IPP, a traveling user could send a print job across the Internet, to be printed on a printer on his corporate network. The user could also find out whether the print request had completed without error.

Microsoft Windows 2000 introduced native support for Internet Printing. The Microsoft Windows 2000 implementation enables users to print directly to an URL, and to view information about print jobs via their browsers. Support for Internet Printing is enabled by default in Microsoft Windows 2000 Server versions. It can also be installed as an optional component on Microsoft Windows 2000 Professional, Windows XP, Windows Server 2003, and Windows Server 2008.

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. If a 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. 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.

How could an attacker exploit the vulnerability?
An attacker could send a specially crafted HTTP POST request to a vulnerable web server that would cause the server to connect to a machine controlled by the attacker acting as a printer using IPP. The attacker would then use specially crafted responses to perform remote code execution on the target server.

What systems are primarily at risk from the vulnerability?
Workstations and servers running IIS with the Internet Printing Protocol (IPP) service enabled are primarily at risk from this vulnerability.

What does the update do?
This security update addresses this vulnerability by validating the data received from remote machines within the Internet Printing Protocol (IPP) service.

When this security bulletin was issued, had this vulnerability been publicly disclosed?
No. Microsoft received information about this vulnerability through responsible disclosure. Microsoft had not received any information to indicate that this vulnerability had been publicly disclosed when this security bulletin was originally issued.

When this security bulletin was issued, had Microsoft received any reports that this vulnerability was being exploited?
Yes, Microsoft is aware of targeted attacks attempting to exploit the vulnerability. However, Microsoft had not seen any examples of proof of concept code published when this security bulletin was originally issued.

Other Information
Acknowledgments

Microsoft thanks the following for working with us to help protect customers:
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CERT/CC for reporting the Integer Overflow in IPP Service Vulnerability - CVE-2008-1446
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Support
•

Customers in the U.S. and Canada can receive technical support from Microsoft Product Support Services at 1-866-PCSAFETY. There is no charge for support calls that are associated with security updates.
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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
•

V1.0 (October 14, 2008): Bulletin published.