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Microsoft DNS Client buffer overflow

Vulnerability Note VU#794580

Original Release Date: 2006-08-08 | Last Revised: 2006-08-08


The Microsoft DNS Client service contains a remote code execution vulnerability that could allow a remote attacker to take complete control of the affected system.


From Microsoft TechNet:

    The Domain Name System (DNS) client service resolves and caches DNS names. The DNS client service must be running on every computer that will perform DNS name resolution. The ability to resolve DNS names is crucial for locating domain controllers in Active Directory domains. The DNS client service is also critical for locating devices identified using DNS name resolution.
The DNS client layer contains an unchecked buffer which could be exploited by a remote and unauthenticated attacker to gain access to the system.


A remote, unauthenticated attacker can gain complete control of a system, including the ability to install programs, view, change or delete data, or create new accounts, by one of the following means:

    1. Sending a specially crafted DNS communication to an affected system from a subnet between the target host and DNS server; or
    2. Convince the target host to make a DNS request to receive a specially crafted record response from an attacking server.


    Apply the update provided by Microsoft. Refer to Microsoft Security Bulletin MS06-041 for more information.

    Block the following DNS related records at network gateways:

      • ATMA
      • TXT
      • X25
      • HINFO
      • ISDN DNS

    Vendor Information


    Microsoft Corporation Affected

    Notified:  August 08, 2006 Updated: August 08, 2006



    Vendor Statement

    We have not received a statement from the vendor.

    Vendor Information

    The vendor has not provided us with any further information regarding this vulnerability.



    Apply the update provided by Microsoft. Refer to Microsoft Security Bulletin MS06-041 for more information.

    If you have feedback, comments, or additional information about this vulnerability, please send us email.

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    This vulnerability was reported by Microsoft, who in turn credit Mark Dowd of ISS X-Force for reporting this vulnerability.

    This document was written by Joseph W Pruszynski.

    Other Information

    CVE IDs: CVE-2006-3441
    Severity Metric: 6.75
    Date Public: 2006-08-08
    Date First Published: 2006-08-08
    Date Last Updated: 2006-08-08 21:12 UTC
    Document Revision: 20

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