Published:
09 August 2000
Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE----- =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2000.204 -- Microsoft Security Bulletin (MS00-055) Patch Available for "Scriptlet Rendering" Vulnerability 10 August 2000 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Microsoft Internet Explorer 4.x Microsoft Internet Explorer 5.x Vendor: Microsoft Operating System: N/A Platform: N/A Impact: Read-only Data Access Access Required: Remote Ref: ESB-2000.101 - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- Microsoft Security Bulletin (MS00-055) - - -------------------------------------- Patch Available for "Scriptlet Rendering" Vulnerability Originally Posted: August 09, 2000 Summary ======= Microsoft has released a patch that eliminates two security vulnerabilities in Microsoft(r) Internet Explorer. The vulnerabilities could allow a malicious web site operator to read - but not add, change, or delete - files on the computer of a visiting user. As discussed in the Patch Availability section below, this patch also provides protection against several security vulnerabilities that have been discussed in previous security bulletins. We have delivered a comprehensive patch in order to minimize the number of patches customers need to apply. Frequently asked questions regarding this vulnerability and the patch can be found at http://www.microsoft.com/technet/security/bulletin/fq00-055.asp Issue ===== There are two vulnerabilities at issue here: - The "Scriptlet Rendering" vulnerability. The ActiveX control that is used to invoked scriptlets is essentially a rendering engine for HTML. However, it will render any file type, rather than rendering HTML files only. This opens the door to a scenario in which a malicious web site operator could provide bogus information consisting of script, solely for the purpose of introducing it into an IE system file with a known name, then use the Scriptlet control to render the file. The net effect would be to make the script run in the Local Computer Zone, at which point it could access files on the user's local file system. - A new variant of the "Frame Domain Verification" vulnerability. As discussed in Microsoft Security Bulletin MS00-033, two functions do not enforce proper separation of frames in the same window that reside in different domains. The new variant involves an additional function with the same flaw. The net effect of the vulnerability would be to enable a malicious web site operator to open two frames, one in his domain and another on the user's local file system, and enable the latter to pass information to the former. In order to exploit either vulnerability, a malicious web site operator would need to know or guess the exact name and path of each file he wanted to view. Even then, he could only view file types that can be opened in a browser window - for instance, .txt or .doc files, but not .exe or .dat files. If the web site were in a Zone in which Active Scripting were disabled, neither vulnerability could be exploited. Affected Software Versions ========================== - Microsoft Internet Explorer 4.x - Microsoft Internet Explorer 5.x Patch Availability ================== - http://www.microsoft.com/windows/ie/download/critical/patch11.htm Note: In addition to eliminating the two vulnerabilities discussed above, this patch also protects against several previously-discussed vulnerabilities. Customers who apply this patch will also be protected against the vulnerabilities discussed in the following Security Bulletins: - Microsoft Security Bulletin MS00-033 - Microsoft Security Bulletin MS00-039 - Microsoft Security Bulletin MS00-049 In addition, for IE 5.5 systems only, this patch also eliminates the vulnerability discussed in Microsoft Security Bulletin MS00-042. Note: Customers who install this patch on versions other than IE 5.01, IE 5.01 SP1, or IE 5.5 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 Q266336. 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 MS00-055, http://www.microsoft.com/technet/security/bulletin/fq00-055.asp - Microsoft Knowledge Base article Q266336 discusses this issue and will be available soon. - Microsoft Security Bulletin MS00-033, Patch Available for "Frame Domain Verification", "Unauthorized Cookie Access", and "Malformed Component Attribute" Vulnerabilities, http://www.microsoft.com/technet/security/bulletin/ms00-033.asp - Microsoft Security Bulletin MS00-039, Patch Available for "SSL Certificate Validation" Vulnerabilities, http://www.microsoft.com/technet/security/bulletin/ms00-039.asp - Microsoft Security Bulletin MS00-042, Patch Available for "Active Setup Download" Vulnerability, http://www.microsoft.com/technet/security/bulletin/ms00-042.asp - Microsoft Security Bulletin MS00-049, Patches Available for "Office HTML" and "IE Script" Security Vulnerabilities, http://www.microsoft.com/technet/security/bulletin/ms00-049.asp - 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 Product Support Services is available at http://support.microsoft.com/support/contact/default.asp. Acknowledgments =============== Microsoft thanks Juan Carlos Garcia Cuartango of Spain (www.kriptopolis.com) for reporting the "Scriptlet Rendering" issue to us and working with us to protect customers. Revisions ========= - August 09, 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 09, 2000 - -----BEGIN PGP SIGNATURE----- Version: PGP Personal Privacy 6.5.3 iQEVAwUBOZILIo0ZSRQxA/UrAQHgvAf/SmVmDZX/fUfIe4HKeE7A0JEjQrdmqCDf 9x41x3ggl8PKmhP7JieNbrJRbb5OgVCFrPVUQuFMrVULSFvBydNuprFUE/ZW2cOr ZqiDy6aEzDzWzOaY9UZTVBJwFQ0Iuz+W+t3aKeKxBAJYOqHC5p7R29cjL/zS17o1 Xynoz4oi8PE/wmXQDOyCHict6lRRvTOrhHbUPzvelOvmweScMD11TMqBLX+rpARE urSqSdzoN5EqdEFdskIUb+4rgMWvQpeDjjBHwsT0zULTxaiUsJPw66hmWPXf8Uaa r3z5v+WGRJEcd4RZl3oKQ/lNm+gtQsf0qhN8ztB9Rcsm3mYxjsCkPw== =yLqQ - -----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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