-----BEGIN PGP SIGNED MESSAGE----- Microsoft Security Bulletin (MS00-043) - -------------------------------------- Patch Available for "Malformed E-mail Header" Vulnerability Originally posted: July 18, 2000 Summary ======= Microsoft has released a patch that eliminates a security vulnerability in Microsoft(r) Outlook(r) and Outlook Express. Under certain conditions, the vulnerability could allow a malicious user to cause code of his choice to execute on another user's computer. Frequently asked questions regarding this vulnerability and the patch can be found at http://www.microsoft.com/technet/security/bulletin/fq00-043.asp Issue ===== A component shared by Outlook and Outlook Express contains an unchecked buffer in the functionality that parses e-mail headers when downloading mail via either POP3 or IMAP4. By sending an e-mail that overruns the buffer, a malicious user could cause either of two effects to occur when the mail was downloaded from the server by an affected e-mail client: - If the affected field were filled with random data, the e-mail could be made to crash. - If the affected field were filled with carefully-crafted data, the e-mail client could be made to run code of the malicious user's choice. Customers who have installed Internet Explorer 5.01 Service Pack 1, and customers who have installed Internet Explorer 5.5 on any system other than Windows 2000, would not be affected by this vulnerability. Likewise, Outlook users who have configured Outlook to use only MAPI services would not be affected, regardless of what version of Internet Explorer they have installed. Affected Software Versions ========================== - Microsoft Outlook Express 4.0 - Microsoft Outlook Express 4.01 - Microsoft Outlook Express 5.0 - Microsoft Outlook Express 5.01 - Microsoft Outlook 97 - Microsoft Outlook 98 - Microsoft Outlook 2000 Patch Availability ================== The vulnerability can be eliminated by a default installation of either of the following upgrades: - Internet Explorer 5.01 Service Pack 1, http://www.microsoft.com/Windows/ie/download/ie501sp1.htm - Internet Explorer 5.5 on any system except Windows 2000, http://www.microsoft.com/windows/ie/download/ie55.htm Note: A non-default installation of IE 5.01 SP1 or IE 5.5 also will eliminate this vulnerability, as long as an installation method is chosen that installs upgraded Outlook Express components. Note: When installed on a Windows 2000 machine, IE 5.5 does not install upgraded Outlook Express components, and therefore does not eliminate the vulnerability. However, Windows 2000 Service Pack 1 will install IE 5.5 and upgrade the Outlook Express components at the same time. Note: Patches will be available shortly that will eliminate the vulnerability without requiring a full version upgrade. When they are available, we will update this bulletin and re-release it. 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 MS00-043, http://www.microsoft.com/technet/security/bulletin/fq00-043.asp - Microsoft Knowledge Base article Q267884 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. Acknowledgments =============== Microsoft thanks USSR Labs (www.ussrback.com) for reporting this issue to us and working with us to protect customers. Revisions ========= - July 18, 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 July 18,2000 (c) 2000 Microsoft Corporation. All rights reserved. Terms of use. -----BEGIN PGP SIGNATURE----- Version: PGP Personal Privacy 6.5.3 iQEVAwUBOXVWQ40ZSRQxA/UrAQGJEwf+K8F9KpiEtxihrCYnYugA8U3A0mF1c+rk 929pfyQsaZfWaMa+VNg5mXxWD6JkTeZs9xU90QTgKp0DjYOuVaf65Mh6eRc/byXr KjAUGVeemkwXoIL/YtGsupTUW5I1u9OIB02FDlQm8RVnQ2uM/hTa1M9eQoQSk1nI VFb0WESomJi6q8VKOm8QjC55zbq6wOWvGVFWzvXvaCN06I8fqe2YpKiqOHI/1dV2 yHZlMH41yl9zdZ0eu+A8vKBQtojLoPuHx3E9tT6K9K2GIHBuIRWprYJq9dOvSq1H kyCkQBOf9PDvjSsiGxZFln8jOOTA2WuLEJQ+nTFDy9mX0JR+2U1UXw== =AnnD -----END PGP SIGNATURE----- ******************************************************************* You have received this e-mail bulletin as a result of your registration to the Microsoft Product Security Notification Service. 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