Microsoft Security Advisory (921923) Released

[Dr.Melzer]

What is this alert?

This alert is to notify you that Microsoft has released Security Advisory (921923) - Proof of Concept Code Published Affecting the Remote Access Connection Manager Service - on 23 June 2006.

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Purpose of Security Advisory 921923
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Security Advisory 921923 provides customers with initial notification that exploit code has been published on the Internet for the vulnerability that is addressed by Microsoft security bulletin MS06-025.

Security Advisory 921923 provides an overview of the issue, details on affected components, suggested actions, frequently asked questions (FAQ) and links to additional resources.

Microsoft is not currently aware of active attacks that use this exploit code or of customer impact at this time. However, Microsoft is actively monitoring this situation to keep customers informed and to provide customer guidance as necessary.

Our investigation of this exploit code has verified that it does not affect customers who have installed the updates detailed in MS06-025 on their computers. Microsoft continues to recommend that customers apply the updates to the affected products by enabling the Automatic Updates feature in Windows.

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Mitigating Factors
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* Customers who have installed the MS06-025 security update are not affected by this vulnerability.

* Windows 2000 systems are primarily at risk from this vulnerability. Customers running Windows 2000 should deploy MS06-025 as soon as possible or disable the Remote Access Connection Manager (RASMAN) service.

* On Windows XP Service Pack 2, Windows Server 2003 and Windows Server 2003 Service Pack 1 the attacker would need to have valid logon credentials in order to exploit the vulnerability.

* This issue does not affect Windows 98, Windows 98 SE, or Windows Millennium Edition.

[Dr.Melzer]

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Answers to Common Questions
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Q: Is this a security vulnerability that requires Microsoft to issue a security update?

A: No. Customers who have installed the MS06-025 security update are not affected by this vulnerability. No additional update is required.

Q: What causes this threat?

A: An unchecked buffer in Routing and Remote Access technologies specifically affecting the Remote Access Connection Manager Service (RASMAN)

Q: What does the feature do?

A: The Remote Access Connection Manager (RASMAN) is a service that handles the details of establishing the connection to the remote server. This service also provides the client with status information during the connection operation. The Remote Access Connection Manager starts automatically when an application loads the RASAPI32.DLL

Q: What might an attacker use this function to do?

A: An attacker who successfully exploited this vulnerability could take complete control of the affected system.

Q: Are there any known issues with installing Microsoft Security Update MS06-025 that protects against this threat?

A: Microsoft Knowledge Base Article 911280 documents the currently known issues that customers may experience when they install the security update. Only customers who use dial-up connections that use scripts that configure their device for parity, stop bits or data bits or a post-connect terminal window or dial-up scripting, are affected by the issues identified in the KB article. If customers do not use any of the dial-up scenarios identified they are encouraged to install the update immediately.

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Recommendations
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Review Security Advisory 921923 for an overview of the issue, details on affected components, mitigating factors, suggested actions, frequently asked questions (FAQ) and links to additional resources.

Review Microsoft Knowledge Base Article 911280 to learn about currently known issues customers may experience when they install security update MS06-025.

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Additional Resources
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* Security Advisory 921923 - Proof of Concept Code Published Affecting the Remote Access Connection Manager Service.
http://www.microsoft.com/technet/sec...ry/921923.mspx

* Microsoft KB Article 911280 - MS06-025: Vulnerability in Routing and Remote Access could allow remote code execution:
http://support.microsoft.com/kb/911280

* Security Bulletin MS06-025: Vulnerability in Routing and Remote Access could allow remote code execution:
http://www.microsoft.com/technet/sec.../ms06-025.mspx

* MSRC Blog:
http://blogs.technet.com/msrc/
Note: check the MSRC Blog periodically as new information may appear there.

If you have any questions regarding this alert please contact your Technical Account Manager or Application Development Consultant.

Thank you,
Microsoft PSS Security Team