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-----BEGIN PGP SIGNED MESSAGE----- =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2001.230 -- Microsoft Security Bulletin MS01-030 (version 2.0) Incorrect Attachment Handling in Exchange OWA Can Execute Script 12 June 2001 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Exchange 5.5 Exchange 2000 Vendor: Microsoft Operating System: Windows Impact: Access Privileged Data Execute Arbitrary Code/Commands Access Required: Remote Ref: ESB-2001.227 - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- - - ---------------------------------------------------------------------- Title: Incorrect Attachment Handling in Exchange OWA Can Execute Script Released: 06 June 2001 Revised: 08 June 2001 (version 2.0) Software: Exchange 5.5, Exchange 2000 Impact: Run code of attacker's choice on mail client Bulletin: MS01-030 Microsoft encourages customers to review the Security Bulletin at: http://www.microsoft.com/technet/security/bulletin/MS01-030.asp. - - ---------------------------------------------------------------------- Reason for Revision: ==================== - Exchange 5.5 has been determined to be affected by the vulnerability. We have developed an Exchange 5.5 patch. - The originally released Exchange 2000 patch has been determined to contain a regression error that can cause performance problems on the servers it is installed on. We have eliminated the regression error and updated the patch; we recommend that customers who installed the original patch install the updated one. Issue: ====== OWA is a service of Exchange Server that allows users to use a web browser to access their Exchange mailbox. However, a flaw exists in the interaction between OWA and IE for message attachments. If an attachment contains HTML code including script, the script will be executed when the attachment is opened, regardless of the attachment type. Because OWA requires that scripting be enabled in the zone where the OWA server is located, this script could take action against the user's Exchange mailbox. An attacker could use this flaw to construct an attachment containing malicious script code. The attacker could then send the attachment in a message to the user. If the user opened the attachment in OWA, the script would execute and could take action against the user's mailbox as if it were the user, including, under certain circumstances, manipulation of messages or folders. Mitigating Factors: ==================== - The vulnerability could only be exploited if the user were using OWA in conjunction with IE. - The vulnerability is only exploitable by attachments that are received via OWA. In general, an attacker would have no way to determine whether a user would open an attachment using OWA rather than an Outlook client. - An attacker's ability to exploit this vulnerability would require that she entice the user to open an attachment from an untrusted source. Best practices recommend against opening any attachment from an unknown or untrusted source. Patch Availability: =================== - A patch is available to fix this vulnerability. Please read the Security Bulletin http://www.microsoft.com/technet/security/bulletin/ms01-030.asp for information on obtaining this patch. Acknowledgment: =============== - Joao Gouveia (tharbad@kaotik.org) - - --------------------------------------------------------------------- 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 iQEVAwUBOyFx9Y0ZSRQxA/UrAQE09wf9EU1CY24W9qxrMtJ6dOj9M7qbb3uE8PIt PL5hAxp9ivS7qJS0VUx7HBUUm+9Q2aJco/ePAWxWZIzJyMjS73Us/8+15yZyRrsM 3wyynyxoaT1LI+rwMyJvzCb9RGdVgvZk1Taj6C/voUNjoQqQsuIJ/L/4+hL22OLu cCHq9xUleeQvA4BM4QCvaA8+33bDrBAKKVrZ0Mx0chgldHdJEqt1DcN2yxQLOonw nADgl0LIqlOnJ9XOteZeKY7q8rU9NgV38EfeICjjGqrVJR1ZN6U4jI/vYFkRzIBy EWdPDlEddIvX9VpBkmtNrqiD6FVTFTjwjwizdJ9nHlM8l4EyFzMW/Q== =I9qJ - -----END PGP SIGNATURE----- - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. 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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 iQCVAwUBOyY+Yyh9+71yA2DNAQGHegP/QOnYz/6135PGptBbTv6HFw8BIgpKU4tY CXdrAMGz1tdPwEdK8clC1bzSs4NptAqJwjVaPWcDLCdMt96MDxcJDhIN3gFVKrKz DXWYvKKAWKkBl9Zwr1hLQI48UTVtGKYphgQJUzgE/aMS/xoexAvRfUhTFROc72CN WTXhTSwY6ys= =UGfH -----END PGP SIGNATURE-----