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-----BEGIN PGP SIGNED MESSAGE----- =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2000.195 -- Microsoft Security Bulletin (MS00-054) Patch Available for "Malformed IPX Ping Packet" Vulnerability 4 August 2000 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: NWLink Vendor: Microsoft Operating System: Windows 95 Windows 98 Windows 98 SE Platform: N/A Impact: Denial of Service - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- Microsoft Security Bulletin (MS00-054) - - -------------------------------------- Patch Available for "Malformed IPX Ping Packet" Vulnerability Date Published: August 03, 2000 Summary ======= Microsoft has released a patch that eliminates a security vulnerability in Microsoft(r) Windows 95, 98 and 98 Second Edition. The vulnerability could be used to cause an affected system to fail, and depending on the number of affected machines on a network, potentially could be used to flood the network with superfluous data. The affected system component generally is present only if it has been deliberately installed. Frequently asked questions regarding this vulnerability and the patch can be found at http://www.microsoft.com/technet/security/bulletin/fq00-054.asp Issue ===== The Microsoft IPX/SPX protocol implementation (NWLink) supports the IPX Ping command via the diagnostic port 0x456. Because of a flaw in the implementation of the protocol in Windows 95, Windows 98 and Windows 98 Second Edition, NWLink in these systems will respond to an IPX ping packet even when the source network address has been purposely modified to a broadcast address. This would give a malicious user an opportunity to launch an attack by broadcasting a single ping request - each affected machine that received the ping would respond to it, potentially resulting in a broadcast storm. In a large network, this could temporarily swamp the network's bandwidth. In addition, upon seeing its own response, each affected machine would attempt to process it, triggering a scenario that would culminate in the machine's failure. A machine that failed due to this vulnerability could be put back into service by rebooting. IPX is not installed by default in Windows 98 and 98 Second Edition, and is only installed by default in Windows 95 if there is a network card present in the machine at installation time. Even when IPX is installed, a malicious user's ability to exploit this vulnerability would depend on whether he could deliver a Ping packet to an affected machine. Routers frequently are configured to drop IPX packets, and if such a router lay between the malicious user and an affected machine, he could not attack it. Routers on the Internet, as a rule, do not forward IPX packets, and this would tend to protect intranets from outside attack, as well as protecting machines connected to the Internet via dial-up connections. As discussed in the FAQ, the most likely scenario in which this vulnerability could be exploited would be one in which a malicious user on an intranet would attack affected machines on the same intranet, or one in which a malicious user on the Internet attacked affected machines on on his cable modem or DSL subnet. Affected Software Versions ========================== - Microsoft Windows 95 - Microsoft Windows 98 - Microsoft Windows 98 Second Edition Patch Availability ================== - Microsoft Windows 95: http://download.microsoft.com/download/win95/Update/8982/ W95/EN-US/265334US5.EXE - Microsoft Windows 98 and Windows 98 Second Edition: http://download.microsoft.com/download/win98/Update/8982/ W98/EN-US/265334USA8.EXE Note: Line breaks have been inserted into the URLs above for readability. Note: Additional security patches are available at the Microsoft Download Center More Information ================ Please see the following references for more information related to this issue. - Frequently Asked Questions: Microsoft Security Bulletin MS00-054, http://www.microsoft.com/technet/security/bulletin/fq00-054.asp - Microsoft Knowledge Base article Q265334 discusses this issue and will be available soon. - Microsoft TechNet Security web site, http://www.microsoft.com/technet/security/default.asp Obtaining Support on this Issue =============================== This is a fully supported patch. Information on contacting Microsoft Technical Support is available at http://support.microsoft.com/support/contact/default.asp. Revisions ========= - August 03, 2000: Bulletin Created. - - ------------------------------------------------------------------ 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. Last Updated August 03, 2000 - -----BEGIN PGP SIGNATURE----- Version: PGP Personal Privacy 6.5.3 iQEVAwUBOYov1o0ZSRQxA/UrAQFL3gf9GrIrkR6IAEWuOC1sxYugO+eOcrqs9bgk oREHUN/F6E7CTZIC0fUjcHVfKPl1d7fpeihZQkALUOks3MxP0E6Z9NiuodQ2wDi8 bBmTfz9+dUoGw7Rs8GIKot7mCPLcjFn8GFxTGudhlP2OMXwr+meM5RZ7ag0QiS2G RAo28RaTv3RPTa2GwipK8LwatvoJjgf6nFhXHBhY4jkGS7b9VVi60aliPjeYVNN1 7Gcb3HV0ceZ0tX1M6WNo3jK0kViR2JdllyXNbLTJ0RtYuUBdd4O68IzGVSV7ciXd KzypLzKwiUsn14o+gaYqBJmZ6ldr+OJskm9OJH6xmY07EDjw4VpJxg== =yPjC - -----END PGP SIGNATURE----- - --------------------------END INCLUDED TEXT-------------------- This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to use any or all of this information is the responsibility of each user or organisation, and should be done so in accordance with site policies and procedures. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the original authors to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/Information/advisories.html If you believe that your system has been compromised, contact AusCERT or your representative in FIRST (Forum of Incident Response and Security Teams). Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). 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