Published:
18 November 2001
Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE-----
===========================================================================
AUSCERT External Security Bulletin Redistribution
ESB-2001.489 -- Microsoft Security Bulletin MS01-055 (Version 2.0)
Cumulative Patch for IE
19 November 2001
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: Internet Explorer 5.5
Internet Explorer 6.0
Vendor: Microsoft
Impact: Access Privileged Data
Access Confidential Data
Modify Arbitrary Files
Increased Privileges
Access Required: Remote
Ref: ESB-2001.478
- --------------------------BEGIN INCLUDED TEXT--------------------
- -----BEGIN PGP SIGNED MESSAGE-----
- - ----------------------------------------------------------------------
Title: 13 November 2001 Cumulative Patch for IE
Released: 08 November 2001
Revised: 13 November 2001 (version 2.0)
Software: Internet Explorer
Impact: Exposure and altering of data in cookies
Max Risk: Moderate
Bulletin: MS01-055
Microsoft encourages customers to review the Security Bulletin at:
http://www.microsoft.com/technet/security/bulletin/MS01-055.asp.
- - ----------------------------------------------------------------------
Reason for Revision:
====================
On November 08, 2001, Microsoft released the original version of
this bulletin. In it, we detailed a work-around procedure that
customers could implement to protect themselves against a publicly
disclosed vulnerability. On November 13, 2001, we released a patch
that, when applied, eliminates all known vulnerabilities affecting
IE 5.5 and IE 6. We therefore expanded the scope of the bulletin to
discuss all of the vulnerabilities the patch addresses. Customers
who disabled Active Scripting per the original version of this
bulletin can re-enable it after installing this patch.
Issue:
======
In addition to eliminating all previously discussed vulnerabilities
affecting IE 5.5 Service Pack 2 and IE 6, the patch also eliminates
three newly discovered ones:
The first two involve how IE handles cookies across domains.
Although the underlying flaws are completely unrelated, the scope
is exactly the same - in each case, a malicious user could
potentially craft a URL that would allow them to gain unauthorized
access to a user's cookies and potentially modify the values
contained in them. Because some web sites store sensitive
information in a user's cookies, this could allow personal
information to be compromised. Both vulnerabilities could be
exploited either by hosting specially crafted URL's on a web page
or by sending them to the victim in an HTML email.
The third vulnerability is a new variant of a vulnerability
discussed in Microsoft Security Bulletin MS01-051 affecting how
IE handles URLs that include dotless IP addresses. If a web site
were specified using a dotless IP format (e.g.,
http://031713501415 rather than http://207.46.131.13), and the
request were malformed in a particular way, IE would not recognize
that the site was an Internet site. Instead, it would treat the
site as an intranet site, and open pages on the site in the
Intranet Zone rather than the correct zone. This would allow the
site to run with fewer security restrictions than appropriate.
This vulnerability does not affect IE 6.
Mitigating Factors:
====================
Cookie Handling Vulnerabilities:
- To exploit either vulnerability, the attacker would need to
entice the user into visiting a particular web site or opening
an HTML e-mail containing the malformed URL.
- The Outlook Email Security Update (which is included as part
of Outlook 2002 in Office XP) would protect the user against the
mail-borne attack scenario.
- Users who have set Outlook Express to use the "Restricted Sites"
Zone are not affected by the mail-borne attack scenario, because
the "Restricted Sites" zone sets Active Scripting to disabled.
Note that this is the default setting for Outlook Express 6.0.
Users of Outlook Express 6.0 should verify that Active Scripting
is still disabled in the Restricted Sites Zone.
Zone Spoofing Vulnerability:
- The default settings in the Intranet Zone differ in only a few
ways from those of the Internet Zone. The differences are
enumerated in the FAQ in MS01-051, but none would allow
destructive action to be taken.
Patch Availability:
===================
- A patch is available to fix this vulnerability. Please read the
Security Bulletin at
http://www.microsoft.com/technet/security/bulletin/ms01-055.asp
for information on obtaining this patch.
Acknowledgment:
===============
- Marc Slemko for reporting one of the cookie handling issues.
- - ---------------------------------------------------------------------
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
iQEVAwUBO/H5y40ZSRQxA/UrAQFvvwf9E9P5Hou56ad+W4l3Bw+7ow97ehns9fqn
bipOsViS4Sv7PqmPPughy0e78y4bA1uvPxSZEvJRhmoV1qP94BY34JE9JaLu+9FV
QZcXPEBeRHYN8JeARDhT9voWUWa36Z0ehz47K7GjHxgKhOt3FKhkWZS9oU37XpOd
ScMG5VxVXMYPD1HPzrGyZqyDE4Mmgxpxw9PmtjZQG2NDWkEAfCXoTNfiyxgK4JuC
a0CCi0AW+GlNjIDl2OvWnWCWQjGXpi/kRi8cX2QgyLruWAeP4M4sL6b9rF2dcHV4
6tc52zz9vBwWN8I+0wZT3CqqxYNjSukSbuDbNbLiwYie98z8z0sp/g==
=dB2K
- -----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
iQCVAwUBO/kJwyh9+71yA2DNAQF0+QP+K5Ue27tzLajpAx3FIxpX+Bvp9h/rsWVx
tSCSq4eDtA38oErQ2ub+sn/nyvaWjeloFV0g1KrBDYmlaIaS/eiLz9KVniqOemnq
3WcGc9D7DylFRFepcfcbz/h5BeDKDuyhzJ5U2QAUjlD+EZqGj848YolSCB6LfdSm
Uf7E300PWDc=
=hlgS
-----END PGP SIGNATURE-----