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Title:      Flaw in Windows Function Could Allow Denial of Service
            (823803)
Date:       23 July 2003
Software:   Microsoft Windows NT 4.0 Server
Impact:     Denial of service
Max Risk:   Moderate
Bulletin:   MS03-029

Microsoft encourages customers to review the Security Bulletins at:
http://www.microsoft.com/technet/security/bulletin/MS03-029.asp
http://www.microsoft.com/security/security_bulletins/ms03-029.asp
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Issue:
======
A flaw exists in a Windows NT 4.0 Server file management function
that can cause a denial of service vulnerability. The flaw results
because the affected function can cause memory that it does not own
to be freed when a specially crafted request is passed to it. If
the application making the request to the function does not carry
out any user input validation and allows the specially crafted
request to be passed to the function, the function may free memory
that it does not own. As a result, the application passing the
request could fail.

By default, the affected function is not accessible remotely,
however applications installed on the operating system that are
available remotely may make use of the affected function.
Application servers or Web servers are two such applications that
may access the function. Note that Internet Information Server 4.0
(IIS 4.0) does not, by default, make use of the affected function.

Mitigating Factors:
====================
- -The default installation of Windows NT 4.0 Server is not
vulnerable to a remote denial of service. Additional software that
makes use of the affected file management function must be
installed on the system to expose the vulnerability remotely.
- -If the application calling the affected file management function
carries out input validation, the specially crafted request may not
be passed to the vulnerable function.
- -The vulnerability cannot be used to cause Windows NT 4.0 Server
itself to fail. Only the application that makes the request may
fail.

Risk Rating:
============
 -Moderate

Patch Availability:
===================
 - A patch is available to fix this vulnerability. Please read the
   Security Bulletins at
   http://www.microsoft.com/technet/security/bulletin/ms03-029.asp
   http://www.microsoft.com/security/security_bulletins/ms03-029.asp
   for information on obtaining this patch.

Acknowledgment:
===============
 - Matt Miller and Jeremy Rauch of @stake, http://www.atstake.com

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