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Title:      Invalid Universal Plug and Play Request can Disrupt
            System Operation
Date:       01 November 2001
Software:   Windows 98, Windows ME, Windows XP
Impact:     Denial of Service
Bulletin:   MS01-054

Microsoft encourages customers to review the Security Bulletin at:
http://www.microsoft.com/technet/security/bulletin/MS01-054.asp.
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Issue:
======
The Universal Plug and Play (UPnP) service allows computers to
discover and use network-based devices. Windows ME and XP include
native UPnP services; Windows 98 and 98SE do not include a native
UPnP service, but one can be installed via the Internet Connection
Sharing client that ships with Windows XP. 

A vulnerability results because the UPnP service does not correctly
handle certain types of invalid UPnP requests. On Windows 98, 98SE,
and ME systems, receiving such a request could cause a variety of
effects ranging from slow performance to system failure. On
Windows XP, the effect is less serious as the flaw consists of a
memory leak. Each time a Windows XP system received such a request,
a small amount of system memory would become unavailable; 
if repeated many times, it could deplete system resources to
the point where performance slowed or stopped altogether. 

Mitigating Factors:
====================

 - Standard firewalling practices (specifically, blocking ports 1900
   and 5000) could be used to protect corporate networks from
   Internet-based attacks.
 
 - On Windows 98 and 98SE, there is no native UPnP support for these
   systems. Windows 98 and 98SE systems would only be affected if
   the Internet Connection Sharing Client from Windows XP had been
   installed on the system. 

 - On Windows ME, UPnP supportis neither installed nor running by
   default. (However, some OEMs do configure pre-built systems
   with the service installed and running). 

 - On Windows XP, the Internet Connection Firewall, which runs
   by default, would impede an attacker's ability to locate and
   attack the system. 

Patch Availability:
===================
 - A patch is available to fix this vulnerability. Please read the 
   Security Bulletin at
   http://www.microsoft.com/technet/security/bulletin/ms01-054.asp
   for information on obtaining this patch.

Acknowledgment:
===============
 - 'Ken' from FTU (franklin_tech_unlimited@yahoo.com)

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