Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE-----
===========================================================================
AUSCERT External Security Bulletin Redistribution
ESB-2003.0073 -- Microsoft Security Bulletin MS03-004
Cumulative Patch for Internet Explorer (810847)
06 February 2003
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: Internet Explorer 5.01
Internet Explorer 5.5
Internet Explorer 6.0
Vendor: Microsoft
Operating System: Windows 98SE
Windows ME
Windows NT
Windows 2000
Windows XP
Platform: i386
IA-64
Impact: Execute Arbitrary Code/Commands
Access Privileged Data
Access Required: Remote
Ref: ESB-2002.677
Comment: CVE Id: CAN-2002-1326
CAN-2002-1328
- --------------------------BEGIN INCLUDED TEXT--------------------
- -----BEGIN PGP SIGNED MESSAGE-----
- - -------------------------------------------------------------------
Title: Cumulative Patch for Internet Explorer (810847)
Date: 05 February 2003
Software: Microsoft Internet Explorer
Impact: Allow an attacker to execute commands on a user's
system.
Max Risk: Critical
Bulletin: MS03-004
Microsoft encourages customers to review the Security Bulletins at:
http://www.microsoft.com/technet/security/bulletin/ms03-004.asp
http://www.microsoft.com/security/security_bulletins/ms03-004.asp
- - -------------------------------------------------------------------
Issue:
======
This is a cumulative patch that includes the functionality of all
previously released patches for IE 5.01, 5.5, 6.0. In addition, it
eliminates two newly discovered vulnerabilities involving Internet
Explorer's cross-domain security model - which keeps windows of
different domains from sharing information. These flaws results in
Internet Explorer because incomplete security checking causes
Internet Explorer to allow one website to potentially access
information from another domain when using certain dialog boxes.
In order to exploit this flaw, an attacker would have to host a
malicious web site that contained a web page designed to exploit this
particular vulnerability and then persuade a user to visit that site.
Once the user has visited the malicious web site, it would be
possible for the attacker to run malicious script by misusing a
dialog box and cause that script to access information in a different
domain. In the worst case, this could enable the web site operator to
load malicious code onto a user's system. In addition, this flaw
could also enable an attacker to invoke an executable that was
already present on the local system.
A related cross-domain vulnerability allows Internet Explorer's
showHelp() functionality to execute without proper security
checking. showHelp() is one of the help methods used to display an
HTML page containing help content. showHelp() allows more types of
pluggable protocols than necessary, and this could potentially allow
an attacker to access user information, invoke executables already
present on a user's local system or load malicious code onto a user's
local system.
The requirements to exploit this vulnerability are the same as for
the issue described above: an attacker would have to host and lure a
user to a malicious web site. In this scenario, the attacker could
open a showHelp window to a known local file on the visiting user's
local system and gain access to information from that file by sending
a specially crafted URL to a second showHelp window. The attacker
could also potentially access user information or run code of
attacker's choice.
This cumulative patch will cause window.showHelp( ) to cease to
function. When the latest HTML Help update - which is being released
via Windows Update with this patch - is installed, window.showHelp( )
will function again, but with some limitations (see the caveats
section later in this bulletin). This has been necessary in order to
block the attack vector that might allow a web site operator to
invoke an executable that was already present on a user's local
system.
Mitigating Factors:
====================
- The attacker would have to host a web site that contained a web
page used to exploit either of these cross-domain vulnerabilities.
- The attacker would have no way to force users to visit the site.
Instead, the attacker would need to lure them there, typically by
getting them to click on a link that would take them to the
attacker's site.
- By default, Outlook Express 6.0 and Outlook 2002 open HTML mail
in the Restricted Sites Zone. In addition, Outlook 98 and 2000 open
HTML mail in the Restricted Sites Zone if the Outlook Email Security
Update has been installed. Customers who use any of these products
would be at no risk from an e-mail borne attack that attempted to
exploit this vulnerability unless the user clicked a malicious link
in the email.
- Internet Explorer 5.01 users are not affected by the first
vulnerability.
Risk Rating:
============
- Internet Explorer 5.01: Critical
- Internet Explorer 5.5: Critical
- Internet Explorer 6.0: Critical
Patch Availability:
===================
- A patch is available to fix this vulnerability. Please read the
Security Bulletins at
http://www.microsoft.com/technet/security/bulletin/ms03-004.asp
http://www.microsoft.com/security/security_bulletins/ms03-004.asp
for information on obtaining this patch.
Acknowledgment:
===============
- Andreas Sandblad, Sweden for reporting the cross domain
vulnerability using showhelp.
Home User Security Notification Service
=======================================
Microsoft is now offering the Microsoft Security Update, a security
bulletin notification service for home users. To learn more about
this service, please go to:
http://www.microsoft.com/security/security_bulletins/decision.asp
- - -------------------------------------------------------------------
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 7.1
iQEVAwUBPkFrFI0ZSRQxA/UrAQHlSwf7B/TI09fbp5QgCyJ9tKNovkIZKdkYpWq/
V3R6r7Kc59LF2wNgn+f2SGR8Os0WQofRFiEY2hI1UaT4D8gDyloMmHVIF03HrQ8s
z9KTq41JD3WRX6mnGvReUM9mOI47/XV4IW1A4qfTqhla1S5A1OO74y0zGH7TjNnk
kx3vN+6ihvBq+kJz6/hKXSwPJFAg4lMtiRWCZoxBphaVcYWxBGSX2JxevOHN8XD+
Ufc9tHMOC3K0NesA+KCIolRokO2SYjSi1IWfeL0fZc7BDdUns2/KZ9G75SCtZJEZ
ImLXOwlIH+Ah8qGON5WWE+ha3D7AC6ZO91eX2vWJUXLEu8ZISCyo+A==
=m/kr
- -----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 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 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 member emergencies only.
-----BEGIN PGP SIGNATURE-----
Version: 2.6.3i
Charset: noconv
Comment: http://www.auscert.org.au/render.html?it=1967
iQCVAwUBPkKYIih9+71yA2DNAQE69QP+Kz8zDdLpkBMeSadJ/Cru9B7hznSs0BHw
EUXVFcbBF3pB3r/q2fxhp8htQH5pijWAIdnBzc0BuHxbhSZgzeDqpS/+ebIT86NU
ObMelJlJIyqBpOSNDdfigacQvAWi3xdEpC9FZ9A4pPbd4CVCMufupRYwgboD2UZr
i3HhbTRoajo=
=iQbr
-----END PGP SIGNATURE-----