From secnotif@MICROSOFT.COM Fri Mar 30 20:54:42 2001 From: Microsoft Product Security To: BUGTRAQ@SECURITYFOCUS.COM Date: Thu, 29 Mar 2001 19:00:21 -0800 Subject: [BUGTRAQ] Microsoft Security Bulletin MS01-020 The following is a Security Bulletin from the Microsoft Product Security Notification Service. Please do not reply to this message, as it was sent from an unattended mailbox. ******************************** -----BEGIN PGP SIGNED MESSAGE----- - ---------------------------------------------------------------------- Title: Incorrect MIME Header Can Cause IE to Execute E-mail Attachment Date: 29 March 2001 Software: Microsoft Internet Explorer Impact: Run code of attacker's choice. Bulletin: MS01-020 Microsoft encourages customers to review the Security Bulletin at: http://www.microsoft.com/technet/security/bulletin/MS01-020.asp. - ---------------------------------------------------------------------- Issue: ====== Because HTML e-mails are simply web pages, IE can render them and open binary attachments in a way that is appropriate to their MIME types. However, a flaw exists in the type of processing that is specified for certain unusual MIME types. If an attacker created an HTML e-mail containing an executable attachment, then modified the MIME header information to specify that the attachment was one of the unusual MIME types that IE handles incorrectly, IE would launch the attachment automatically when it rendered the e-mail. An attacker could use this vulnerability in either of two scenarios. She could host an affected HTML e-mail on a web site and try to persuade another user to visit it, at which point script on a web page could open the mail and initiate the executable. Alternatively, she could send the HTML mail directly to the user. In either case, the executable attachment, if it ran, would be limited only by user's permissions on the system. Mitigating Factors: ==================== The vulnerability could not be exploited if File Downloads have been disabled in the Security Zone in which the e-mail is rendered. This is not a default setting in any zone, however. Patch Availability: =================== - A patch is available to fix this vulnerability. Please read the Security Bulletin http://www.microsoft.com/technet/security/bulletin/ms01-020.asp for information on obtaining this patch. Acknowledgment: =============== - Juan Carlos Cuartango (http://www.kriptopolis.com) - --------------------------------------------------------------------- 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. -----BEGIN PGP SIGNATURE----- Version: PGP Personal Privacy 6.5.3 iQEVAwUBOsP2xI0ZSRQxA/UrAQE2Qwf/QCMKq96UCHrLAVZrZG77oLp8Z9uZ+fMg tU6Q2n4iR0SVxckd3uwfuMN7xypztrxwdVk15QhBihuK63J+P/r4XA0Q6tYi6mlF h6vDBZrJyCoJ485HkIZDoiEKd++Uw+D9nCbp0aUjX7c3vbAeBINSRkhXIIJ9JlkL 23UAZBgab2LlL60hX+X47TNl5x6Jc8OQOBNnIWEF3YH3WeVEsALzGI5ewvJbfMvd 3IKedgxf83B0ds0nAMcHOwsZFa+cDAta6AlWxXnwXK6g5ndKqi209Lf3/1vN9fdL h77OTFU+RGUrnLcIhrZV06u+I6U/SE7CF9k3heuyo834QezsLCvq4w== =+KNh -----END PGP SIGNATURE----- ******************************************************************* You have received this e-mail bulletin as a result of your registration to the Microsoft Product Security Notification Service. You may unsubscribe from this e-mail notification service at any time by sending an e-mail to MICROSOFT_SECURITY-SIGNOFF-REQUEST@ANNOUNCE.MICROSOFT.COM The subject line and message body are not used in processing the request, and can be anything you like. To verify the digital signature on this bulletin, please download our PGP key at http://www.microsoft.com/technet/security/notify.asp. For more information on the Microsoft Security Notification Service please visit http://www.microsoft.com/technet/security/notify.asp. For security-related information about Microsoft products, please visit the Microsoft Security Advisor web site at http://www.microsoft.com/security.