DOCUMENT:Q154174 21-FEB-2002 [crossnet] TITLE :Invalid ICMP Datagram Fragments Hang Windows NT, Windows 95 PRODUCT :Windows for Workgroups and Windows NT Networking Issues PROD/VER::3.51,4.0 OPER/SYS: KEYWORDS:kbfile kbnetwork kbWinNT400sp4fix kbgraphxlinkcritical ====================================================================== ------------------------------------------------------------------------------- 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 ------------------------------------------------------------------------------- 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: ====================================================================== 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 ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2002.