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Title:      Unchecked Buffer in Windows Redirector Could Allow
            Privilege Elevation (810577)
Date:       05 February 2003
Software:   Microsoft Windows XP
Impact:     Privilege elevation
Max Risk:   Important
Bulletin:   MS03-005

Microsoft encourages customers to review the Security Bulletins at: 
http://www.microsoft.com/technet/security/bulletin/ms03-005.asp
http://www.microsoft.com/security/security_bulletins/ms03-005.asp
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Issue:
======
The Windows Redirector is used by a Windows client to access files, 
whether local or remote, regardless of the underlying network 
protocols in use. For example, the "Add a Network Place" Wizard or 
the NET USE command can be used to map a network share as a local 
drive, and the Windows Redirector will handle the routing of 
information to and from the network share.

A security vulnerability exists in the implementation of the 
Windows Redirector on Windows XP because an unchecked buffer is 
used to receive parameter information. By providing malformed data 
to the Windows Redirector, an attacker could cause the system to 
fail, or if the data was crafted in a particular way, could run 
code of the attacker's choice. 

Mitigating Factors:
====================
 - An attacker would require the ability to log onto the system 
interactively in order to run programs that use the Windows 
Redirector. This vulnerability cannot be exploited remotely. 
 - Windows XP systems that are not shared between users would not 
be at risk.
 
Risk Rating:
============
 - Windows XP: Important

Patch Availability:
===================
 - A patch is available to fix this vulnerability. Please read the 
   Security Bulletins at

   http://www.microsoft.com/technet/security/bulletin/ms03-005.asp
   http://www.microsoft.com/security/security_bulletins/ms03-005.asp

   for information on obtaining this patch.

Acknowledgment:
===============
 - NSFocus (http://www.nsfocus.com)

Home User Security Notification Service
=======================================
Microsoft is now offering the Microsoft Security Update, a security 
bulletin notification service for home users.  To learn more about 
this service, please go to: 

http://www.microsoft.com/security/security_bulletins/decision.asp

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