-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

===========================================================================
             AUSCERT External Security Bulletin Redistribution

                          ESB-2006.0697 -- [Win]
         Microsoft Internet Explorer VML Buffer Overflow (Update)
                             27 September 2006

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:              Internet Explorer
Publisher:            US-CERT
Operating System:     Windows
Impact:               Execute Arbitrary Code/Commands
Access:               Remote/Unauthenticated
CVE Names:            CVE-2006-3866

Ref:                  AU-2006.0034
                      AL-2006.0082
                      AL-2006.0081

- --------------------------BEGIN INCLUDED TEXT--------------------

- -----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1


                        National Cyber Alert System

                 Technical Cyber Security Alert TA06-262A


Microsoft Internet Explorer VML Buffer Overflow

   Original release date: September 19, 2006
   Last revised: September 26, 2006
   Source: US-CERT


Systems Affected

     * Microsoft Windows
     * Microsoft Internet Explorer


Overview

   Microsoft Internet Explorer (IE) fails to properly handle Vector
   Markup Language (VML) tags. This creates a buffer overflow
   vulnerability that could allow a remote attacker to execute arbitrary
   code.


I. Description

   Microsoft Internet Explorer contains a stack buffer overflow in code
   that handles VML. More information is available in Vulnerability Note
   VU#416092, Microsoft Security Advisory (925568), and Microsoft
   Security Bulletin MS06-055.

   Note that this vulnerability is being exploited.


II. Impact

   By convincing a user to open a specially crafted HTML document, such
   as a web page or HTML email message, a remote attacker could execute
   arbitrary code with the privileges of the user running IE.


III. Solution

Apply update from Microsoft

   Microsoft has provided an update to correct this vulnerability in
   Microsoft Security Bulletin MS06-055.

   This update is available on the Microsoft Update site.

   System administrators may wish to consider using Windows Server Update
   Services (WSUS).

Disable VML support

   Microsoft Security Advisory (925568) suggests the following techniques
   to disable VML support:

     * Un-register Vgx.dll on Windows XP Service Pack 1; Windows XP
       Service Pack 2; Windows Server 2003 and Windows Server 2003
       Service Pack 1

     * Modify the Access Control List on Vgx.dll to be more restrictive

     * Configure Internet Explorer 6 for Microsoft Windows XP Service
       Pack 2 to disable Binary and Script Behaviors in the Internet and
       Local Intranet security zone

   Disabling VML support may cause web sites and applications that use
   VML to function improperly.

Render email as plain text

   Microsoft Security Advisory (925568) suggests configuring Microsoft
   Outlook and Outlook Express to render email messages in plain text
   format.

Do not follow unsolicited links

   In order to convince users to visit their sites, attackers often use
   URL encoding, IP address variations, long URLs, intentional
   misspellings, and other techniques to create misleading links. Do not
   click on unsolicited links received in email, instant messages, web
   forums, or internet relay chat (IRC) channels. Type URLs directly into
   the browser to avoid these misleading links. While these are generally
   good security practices, following these behaviors will not prevent
   exploitation of this vulnerability in all cases, particularly if a
   trusted site has been compromised or allows cross-site scripting.


IV. References

     * Vulnerability Note VU#416092 -
       <http://www.kb.cert.org/vuls/id/416092>

     * Microsoft Security Bulletin MS06-055-
       <http://www.microsoft.com/technet/security/bulletin/ms06-055.mspx>

     * Microsoft Security Advisory (925568) -
       <http://www.microsoft.com/technet/security/advisory/925568.mspx>

     * Securing Your Web Browser-
       <http://www.us-cert.gov/reading_room/securing_browser/#Internet_Explorer>

     * Microsoft Update - <https://update.microsoft.com/microsoftupdate/>

     * CVE-2006-3866 -
       <http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-3866>


 ____________________________________________________________________

   The most recent version of this document can be found at:

     <http://www.us-cert.gov/cas/techalerts/TA06-262A.html>
 ____________________________________________________________________

   Feedback can be directed to US-CERT Technical Staff. Please send
   email to <cert@cert.org> with "TA06-262A Feedback VU#416092" in the
   subject.
 ____________________________________________________________________

   For instructions on subscribing to or unsubscribing from this
   mailing list, visit <http://www.us-cert.gov/cas/signup.html>.
 ____________________________________________________________________

   Produced 2006 by US-CERT, a government organization.

   Terms of use:

     <http://www.us-cert.gov/legal.html>
 ____________________________________________________________________



Revision History

   September 19, 2006: Initial release
   September 21, 2006: Fixed misspelling and removed IE-specific
language from Solution section
   September 26, 2006: Added update information and added a reference
to Microsoft Update




- -----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.1 (GNU/Linux)

iQEVAwUBRRmv0exOF3G+ig+rAQIdWggAq2T6Bj+3EWc2nlkr4bibfzZ1E9n+rluo
+76A1YO0EbV0NjRkj4u12nofUu0XfaGAo/V3R00SjfEYH3OWMky6zyf+PCq7v3NQ
tOUCtwo0gzxRZDeTsiOqmMdY57kbfdeJ+lFYF5Tr07IEMB/gmZjkEqiNPLhyJC5w
zHc51Jo1Favq3XHw5W0x5wd41jTNjt2BkFz44daNIR244HtraMsgK9tiaod8krnF
E8V74cBnTV7Rhhxw+icNANp7CdluriKmh/lemTHU+vKASzpL8QRM18a/Y2zqKL7A
p3Jzns5WzWkYDYkCOrwLFbQGWPlUEMHIR+eOmWdgCyKpEG0OW7H0Qg==
=xk4s
- -----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.

NOTE: Third Party Rights
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 follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.

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 author's website 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/render.html?cid=1980

If you believe that your computer system has been compromised or attacked in 
any way, we encourage you to let us know by completing the secure National IT 
Incident Reporting Form at:

        http://www.auscert.org.au/render.html?it=3192

===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072

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 member emergencies only.
===========================================================================

-----BEGIN PGP SIGNATURE-----
Comment: http://www.auscert.org.au/render.html?it=1967

iQCVAwUBRRm+fih9+71yA2DNAQLn2gP/XCmdkmSxm7KfC533msyPe7/O3i1p6KS3
iQeExTWNPmVwO+mF0ugBh5CzCipAwc6J5AYebjkWqPnqfr2Ne0K0F8G3rd6/6TZj
UYhuuYRz1fQgy3yJEulzhAejk2gDPERg5oKiTAmn3d2CpOHHAidL8tfo72sfTL53
uj45Uzz4Gkc=
=8++W
-----END PGP SIGNATURE-----