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Q154174: Invalid ICMP Datagram Fragments Hang Windows NT, Windows 95

Article: Q154174
Product(s): Windows for Workgroups and Windows NT Networking Issues
Version(s): 3.51,4.0
Operating System(s): 
Keyword(s): kbfile kbnetwork kbWinNT400sp4fix kbgraphxlinkcritical
Last Modified: 21-FEB-2002

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The information in this article applies to:

- Microsoft Windows NT Workstation versions 3.51, 4.0 
- Microsoft Windows NT Server versions 3.51, 4.0 
- Microsoft Windows 95 
- Microsoft Windows NT Server version 4.0, Terminal Server Edition 
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SYMPTOMS
========

Computers running Windows NT or Windows 95 may stop responding (hang) when they
receive corrupted Internet Control Message Protocol (ICMP) datagram fragments
from a client.


RESOLUTION
==========

Microsoft has updated the TCP/IP protocol stack to correct this problem.
Instructions for installing it are available from Microsoft support channels or
directly from the Internet locations below.

NOTE: This hotfix was originally posted on July 7, 1997. A subsequent fix was
completed on January 9, 1998 to address another nearly identical attack and this
hotfix has replaced the original one. The original hotfix is included in Windows
NT 4.0 Service Pack 3. The most recent hotfix is not; however, it is available
from the following Internet locations:

Windows NT 4.0
--------------

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or
Windows NT Server 4.0, Terminal Server Edition. For additional information,
please see the following article in the Microsoft Knowledge Base:

  Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack


For your convenience, the English version of this post-SP3 hotfix has been posted
to the following Internet location. However, Microsoft recommends that you
install Windows NT 4.0 Service Pack 4 to correct this problem.

  ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT40/hotfixes-postSP3/teardrop2-fix

NOTE: Service Pack 3 must be applied to Windows NT 4.0 prior to applying this
fix.

Windows NT 3.51
---------------

NOTE: Service Pack 5 must be applied to Windows NT 3.51 prior to applying this
fix.

This fix should have the following time stamp:

  01/14/98  12:04p               123,824 Tcpip.sys   (Intel)
  01/14/98  12:00p               216,848 Tcpip.sys   (Alpha)

This hotfix has been posted to the following Internet location:

  ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT351/hotfixes-postSP5/teardrop2-fix

Windows 95
----------

This issue is resolved by the following updated file for Windows 95 and OSR2, and
later versions of this file:

  Vip.386  version 4.0.958  dated 1/14/98 9:58am  66,734 bytes

This file is included in the self-extracting Vipup11.exe file.

The following file is available for download from the Microsoft Download Center:

  DownloadDownload Vipup11.exe now
  (http://download.microsoft.com/download/win95upg/tcpip/1/WIN98/EN-US/vipup11.exe)

For additional information about how to download Microsoft Support files, click
the article number below to view the article in the Microsoft Knowledge Base:

  Q119591 How to Obtain Microsoft Support Files from Online Services

Microsoft used the most current virus detection software available on the date of
posting to scan this file for viruses. Once posted, the file is housed on secure
servers that prevent any unauthorized changes to the file.

The following files are installed by Vipup11.exe:

  File name  Version    Date/Time        Size     Destination folder
  ------------------------------------------------------------------
  Vip.386    4.00.958   1/14/98 9:58am   66,734   Windows\System

STATUS
======

Microsoft has confirmed this problem could result in some degree of security
vulnerability in Windows NT version 4.0. This problem was first corrected in
Windows NT 4.0 Service Pack 4.0 and Windows NT Server 4.0, Terminal Server
Edition Service Pack 4.


Microsoft has confirmed this problem could result in some degree of security
vulnerability in Windows NT version 3.51. A fully supported fix is now
available, but it has not been fully regression tested and should only be
applied to systems determined to be at risk of attack. Please evaluate your
system's physical accessibility, network and Internet connectivity, and other
factors to determine the degree of risk to your system. If your system is
sufficiently at risk, Microsoft recommends you apply this fix. Otherwise, wait
for the next Windows NT service pack, which will contain this fix. Please
contact Microsoft Technical Support for more information.


Microsoft has confirmed this to be a problem in Microsoft Windows 95 and OEM
Service Release 2 (OSR2). An update to address this problem is now available,
but is not fully regression tested and should be applied only to computers
experiencing this specific problem. Unless you are severely impacted by this
specific problem, Microsoft does not recommend implementing this update at this
time. Contact Microsoft Technical Support for additional information about the
availability of this update.

Additional query words:

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Keywords          : kbfile kbnetwork kbWinNT400sp4fix kbgraphxlinkcritical 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT351search kbWinNT400search kbWinNTW351search kbWinNTW351 kbWinNTSsearch kbWinNTS400search kbWinNTS400 kbWinNTS351 kbNTTermServ400 kbNTTermServSearch kbWinNTS351search kbWin95search kbZNotKeyword3
Version           : :3.51,4.0
Issue type        : kbbug
Solution Type     : kbfix

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