Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE----- =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2000.101 -- Microsoft Security Bulletin (MS00-033) Patch Available for "Frame Domain Verification", "Unauthorized Cookie Access", and "Malformed Component Attribute" Vulnerabilities 18 May 2000 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Microsoft Internet Explorer 4 Microsoft Internet Explorer 5 Vendor: Microsoft Operating System: MS Windows Platform: N/A Impact: Execute Arbitrary Code Access Privileged Data Access Required: Remote - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- Microsoft Security Bulletin (MS00-033) - - -------------------------------------- Patch Available for "Frame Domain Verification", "Unauthorized Cookie Access", and "Malformed Component Attribute" Vulnerabilities Originally Posted: May 17, 2000 Summary ======= Microsoft has released a comprehensive patch that eliminates three security vulnerabilities in Microsoft(r) Internet Explorer 4 and 5: - The "Frame Domain Verification" vulnerability, which could allow a malicious web site operator to read, but not change or add, files on the computer of a visiting user. - The "Unauthorized Cookie Access" vulnerability, which could allow a malicious web site operator to access "cookies" belonging to a visiting user. - The "Malformed Component Attribute" vulnerability, which could allow a malicious web site operator to run code of his choice on the computer of a visiting user. Issue ===== The three security vulnerabilities eliminated by this patch are unrelated to each other except by the fact that they all occur in the same .dll. We have packaged them together for customer convenience. The vulnerabilities are: - "Frame Domain Verification" vulnerability. When a web server opens a frame within a window, the IE security model should only allow the parent window to access the data in the frame if they are in the same domain. However, two functions available in IE do not properly perform domain checking, with the result that the parent window could open a frame that contains a file on the local computer, then read it. This could allow a malicious web site operator to view files on the computer of a visiting user. The web site operator would need to know (or guess) the name and location of the file, and could only view file types that can be opened in a browser window. - "Unauthorized Cookie Access" vulnerability. By design, the IE security model restricts cookies so that they can be read only by sites within the originator's domain. However, by using a specially-malformed URL, it is possible for a malicious web site operator to gain access to another site's cookie and read, add or change them. A malicious web site operator would need to entice a visiting user into clicking a link in order to access each cookie, and could not obtain a listing of the cookies available on the visitor's system. Even after recovering a cookie, the type and amount of personal information would depend on the privacy practices followed by the site that placed it there. - "Malformed Component Attribute" vulnerability. The code used to invoke ActiveX components in IE has an unchecked buffer and could be exploited by a malicious web site operator to run code on the computer of a visiting user. The unchecked buffer is only exposed when certain attributes are specified in conjunction with each other. The patch also eliminates a new variant of the previously-addressed WPAD Spoofing vulnerability (http://www.microsoft.com/technet/security/bulletin/ms99-054.asp). Affected Software Versions ========================== - Microsoft Internet Explorer 4.0 - Microsoft Internet Explorer 4.01 - Microsoft Internet Explorer 5.0 - Microsoft Internet Explorer 5.01 Patch Availability ================== - http://www.microsoft.com/windows/ie/download/critical/patch6.htm Note: The patches require IE 4.01 Service Pack 2 or IE 5.01 to install. Customers using versions prior to these may receive a message reading "This update does not need to be installed on this system". This message is incorrect. More information is available in KB article Q262509. 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 MS00-033, http://www.microsoft.com/technet/security/bulletin/fq00-033.asp - Microsoft Knowledge Base article Q262509 discusses the overall patch and will be available soon. - Microsoft Knowledge Base articles Q251108 and 255676 discuss the "Frame Domain Verification" vulnerability and will be available soon. - Microsoft Knowledge Base article Q258430 discusses the "Unauthorized Cookie Access" vulnerability and will be available soon. - Microsoft Knowledge Base article Q261257 discusses the "Malformed Component Attribute" vulnerability and will be available soon. - Microsoft Knowledge Base (KB) article Q247333, Web Proxy Auto-Discovery "Spoofing" May Change Proxy Settings, http://www.microsoft.com/technet/support/kb.asp?ID=247333 - 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. Acknowledgments =============== Microsoft thanks the following people for working with us to protect customers: - Mead & Company's Andrew Nosenko for reporting the "Frame Domain Verification" issue to us - Marc Slemko for reporting the "Unauthorized Cookie Access" vulnerability to us. - UNYUN, the Shadow Penguin Security Research Group of Japan, for reporting the "Malformed Component Attribute" vulnerability to us. Revisions ========= - May 17, 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 May 17, 2000 (c) 2000 Microsoft Corporation. All rights reserved. Terms of use. - -----BEGIN PGP SIGNATURE----- Version: PGP 6.0.2 iQEVAwUBOSM9No0ZSRQxA/UrAQGTCggAni1/ZkBUGBT1XnI0anqPhY7+cTu0Q1is GjITriIFM8e0gDC9RxYE4Gjh7/AlvSfUZQz3ApxFzi2ltavJULn7vE7bEFNGhj1a uUvEApqJ/xeLreMMNMQx1sz6HN15U4HJjO9Q9If98fdr0UELkFFciVeJXGSDEYCT f/UcZWKxZIQlxG2QgGAqfMSOrYu/FyYfuTOawIPbwQ3s2kKJ8kH477jS+kpkxzoC I29HpQpW/BMDW3HtkX+HWx2Q592X958j7dkxWsGkCgVbbVCjozOLFRLk57awkHrU mvLezVxT4y1l2NV0xIgEXaoiMPzHGO+Voo7xUdQloSIF+ztMWv9Zkw== =EwPj - -----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). On call after hours for emergencies. -----BEGIN PGP SIGNATURE----- Version: 2.6.3i Charset: noconv Comment: ftp://ftp.auscert.org.au/pub/auscert/AUSCERT_PGP.key iQCVAwUBOXXSqSh9+71yA2DNAQHh0AQAknL1ifFYhnor/JhWclN8ygET8MxlpO5h +4sDMsnMyJ8DPD4V3uoerckXV7JwrestQkU8Lboxqdh5GarDIZmdINfhTfpSutzU FEkbGPTEBs0VqC7zDWO7QVWnnJD5/CCnbMzNCPrR1vfiCn+9IXW6wmKCqLltZdNV cX3q2EZ1Hu8= =5Wwl -----END PGP SIGNATURE-----