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Title:      Unchecked Buffer in Locator Service Could Lead to Code
            Execution (810833)
Date:       22 January, 2003
Software:   Microsoft Windows NT 4.0, Windows 2000, and Windows XP
Impact:     Run code of the attacker's choice 
Max Risk:   Critical
Bulletin:   MS03-001

Microsoft encourages customers to review the Security Bulletins at: 
http://www.microsoft.com/technet/security/bulletin/ms03-001.asp
http://www.microsoft.com/security/security_bulletins/ms03-001.asp
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Issue:
======
The Microsoft Locator service is a name service that maps logical
names to network-specific names. It ships with Windows NT 4.0,
Windows 2000, and Windows XP. By default, the Locator service is
enabled only on Windows 2000 domain controllers and Windows NT 4.0
domain controllers; it is not enabled on Windows NT 4.0 workstations
or member servers, Windows 2000 workstations or member servers,
or Windows XP. 

A security vulnerability results from an unchecked buffer in the
Locator service. By sending a specially malformed request to the
Locator service, an attacker could cause the Locator service to
fail, or to run code of the attacker's choice on the system. 

Mitigating Factors:
====================
 - The Locator service is not enabled by default on any affected
   versions of Windows with the exception of Windows 2000 domain
   controllers and Windows NT 4.0 domain controllers. 

 - A properly-configured firewall would block the calls to the
   Locator service, which would protect an affected machine from
   an Internet-based attack. 

Risk Rating:
============
 - Windows NT 4.0 (Workstations and Member Servers): Moderate 
 - Windows NT 4.0 (Domain Controllers Only): Critical 
 - Windows NT 4.0, Terminal Server Edition: Moderate 
 - Windows 2000 (Workstations and Member Servers): Moderate 
 - Windows 2000 (Domain Controllers Only): Critical 
 - Windows XP: Moderate 

Patch Availability:
===================
 - A patch is available to fix this vulnerability. Please read the 
   Security Bulletins at
   http://www.microsoft.com/technet/security/bulletin/ms03-001.asp
   http://www.microsoft.com/security/security_bulletins/ms03-001.asp

   for information on obtaining this patch.

Acknowledgment:
===============
 -  David Litchfield of Next Generation Security Software Ltd.
    (http://www.nextgenss.com)

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