-----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. If
you do not know who that is, please send an email to auscert@auscert.org.au
and we will forward your request to the appropriate person.

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

iQCVAwUBOyY+Yyh9+71yA2DNAQGHegP/QOnYz/6135PGptBbTv6HFw8BIgpKU4tY
CXdrAMGz1tdPwEdK8clC1bzSs4NptAqJwjVaPWcDLCdMt96MDxcJDhIN3gFVKrKz
DXWYvKKAWKkBl9Zwr1hLQI48UTVtGKYphgQJUzgE/aMS/xoexAvRfUhTFROc72CN
WTXhTSwY6ys=
=UGfH
-----END PGP SIGNATURE-----