Microsoft Security Bulletin MS08-059 – Critical Vulnerability in Host Integration Server RPC Service Could Allow Remote Code Execution (956695)

Microsoft Security Bulletin MS08-059 – Critical
Vulnerability in Host Integration Server RPC Service Could Allow Remote Code Execution (956695)
Published: October 14, 2008

Version: 1.0
General Information
Executive Summary

This security update resolves a privately reported vulnerability in Microsoft Host Integration Server. The vulnerability could allow remote code execution if an attacker sent a specially crafted Remote Procedure Call (RPC) request to an affected system. Customers who follow best practices and configure the SNA RPC service account to have fewer user rights on the system could be less impacted than customers who configure the SNA RPC service account to have administrative user rights.

This security update is rated Critical for all supported editions of Microsoft Host Integration Server 2000, Microsoft Host Integration Server 2004, and Microsoft Host Integration Server 2006. For more information, see the subsection, Affected and Non-Affected Software, in this section.

The security update addresses the vulnerability by validating RPC requests. 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 immediately.

Known Issues. None
Top of sectionTop of section
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
Software Maximum Security Impact Aggregate Severity Rating Bulletins Replaced by this Update

Microsoft Host Integration Server 2000 Service Pack 2 (Server)

Remote Code Execution

Critical

None

Microsoft Host Integration Server 2000 Administrator Client

Remote Code Execution

Critical

None

Microsoft Host Integration Server 2004 (Server)

Remote Code Execution

Critical

None

Microsoft Host Integration Server 2004 Service Pack 1 (Server)

Remote Code Execution

Critical

None

Microsoft Host Integration Server 2004 (Client)

Remote Code Execution

Critical

None

Microsoft Host Integration Server 2004 Service Pack 1 (Client)

Remote Code Execution

Critical

None

Microsoft Host Integration Server 2006 for 32-bit systems

Remote Code Execution

Critical

None

Microsoft Host Integration Server 2006 for x64-based systems

Remote Code Execution

Critical

None
Top of sectionTop of section

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 956695.

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.
Top of sectionTop of section
Vulnerability Information

Severity Ratings and Vulnerability Identifiers
Vulnerability Severity Rating and Maximum Security Impact by Affected Software
Affected Software HIS Command Execution Vulnerability - CVE- 2008-3466 Aggregate Severity Rating

Microsoft Host Integration Server 2000 Service Pack 2

Critical
Remote Code Execution

Critical

Microsoft Host Integration Server 2000 Administrator Client

Critical
Remote Code Execution

Critical

Microsoft Host Integration Server 2004

Critical
Remote Code Execution

Critical

Microsoft Host Integration Server 2004 Service Pack 1

Critical
Remote Code Execution

Critical

Microsoft Host Integration Server 2006

Critical
Remote Code Execution

Critical
Top of sectionTop of section

HIS Command Execution Vulnerability - CVE- 2008-3466

A remote code execution vulnerability exists in the SNA Remote Procedure Call (RPC) service for Host Integration Server. An attacker could exploit the vulnerability by constructing a specially crafted RPC request. The vulnerability could allow remote code execution. An attacker who successfully exploited this vulnerability could take complete control of an affected system.

To view this vulnerability as a standard entry in the Common Vulnerabilities and Exposures list, see CVE-2008-3466.

Mitigating Factors for HIS Command Execution Vulnerability - CVE- 2008-3466

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 who successfully exploited this vulnerability could gain the same user rights as the SNA service account as specified during the install of Host Integration Server. Customers who follow best practices and configure the SNA RPC service account to have fewer user rights on the system could be less impacted than customers who configure the SNA service account to have administrative user rights.
•

For systems with Microsoft Host Integration Server 2000 Administrator Client or the Microsoft Host Integration Server 2004 Client, the default installation does not create or start the SNA Remote Procedure Call (RPC) service where the vulnerability exists. However; the files are installed by default and can be started therefore we highly recommend that customers apply the update if they have a vulnerable version of the product.
Top of sectionTop of section

Workarounds for HIS Command Execution Vulnerability - CVE-2008-3466

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:
•

For Host Integration Server 2004 and Host Integration Server 2006, do not configure the HIS/SNA service to run with an Administrator Account.
•

When first installing Host Integration Server, administrators are prompted for an account to run the SNA RPC service with. Customers should follow best practices and select an account with non-administrative privileges.
•

The SNA service can be configured to use a lower privileged account through the Configuration Tool under the Host Integration Server folder in the Start menu.

Note This workaround is not available for Host Integration Server 2000.

Impact of workaround. None. Following best practices, the SNA service should be run with an account with non-administrative privileges.
•

For Host Integration Server 2000, Host Integration Server 2004 and Host Integration Server 2006, disable the SNA RPC Service.

To disable the affected service change the SnaRpcService service to disabled. This service is used to add performance counters and refresh the bindings when adding link services or additional SNA Server services to a server.

Once these configuration tasks are completed, disable the SNARPC service.

Impact of workaround. Normal runtime operation and additional configuration changes, such as adding connections, are not dependent on the SNARPC service. However, if link services or nodes are added while this service is disabled, the associated performance counters will not be added and the SNA MngAgent service will need to be recycled for the configuration changes to be reflected in the SNA Manager.
Top of sectionTop of section

FAQ for HIS Command Execution Vulnerability - CVE- 2008-3466

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 with full user rights.

What causes the vulnerability?
Specially crafted RPC requests allow remote unauthenticated users to bypass authentication within the SNA RPC service.

What is RPC?
Remote Procedure Call (RPC) is a protocol that a program can use to request a service from a program located on another computer in a network. RPC helps with interoperability because the program using RPC does not have to understand the network protocols that are supporting communication. In RPC, the requesting program is the client and the service-providing program is the server.

What might an attacker use the vulnerability to do?
An attacker who successfully exploited this vulnerability could take complete control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

How could an attacker exploit the vulnerability?
An attacker could try to exploit the vulnerability by creating a specially crafted RPC message and sending the message to an affected system over the RPC TCP/UDP port which is dynamically assigned by Host Integration Server.

What systems are primarily at risk from the vulnerability?
All systems that have the affected Microsoft Host Integration Server installed are at risk from this vulnerability.

What does the update do?
This update removes the vulnerability by restricting access to the administrative functions exposed by RPC.

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?
No. Microsoft had not received any information to indicate that this vulnerability had been publicly used to attack customers and 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:
•

Stephen Fewer of Harmony Security, working with iDefense VCP, for reporting the HIS RPC Buffer Overflow Vulnerability - (CVE-2008-3466)

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.
•

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.