Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE-----
===========================================================================
AUSCERT External Security Bulletin Redistribution
ESB-2002.092 -- Microsoft Security Bulletin MS02-009
Incorrect VBScript Handling in IE can Allow Web Pages to Read Local Files
22 February 2002
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: Internet Explorer 5.01
Internet Explorer 5.6
Internet Explorer 6
Vendor: Microsoft
Operating System: Windows
Impact: Access Privileged Data
Access Required: Remote
- --------------------------BEGIN INCLUDED TEXT--------------------
- -----BEGIN PGP SIGNED MESSAGE-----
- - -
- - ----------------------------------------------------------------------
Title: Incorrect VBScript Handling in IE can Allow Web Pages to
Read Local Files
Date: 21 February 2002
Software: Internet Explorer
Impact: Information Disclosure
Max Risk: Critical
Bulletin: MS02-009
Microsoft encourages customers to review the Security Bulletin at:
http://www.microsoft.com/technet/security/bulletin/MS02-009.asp.
- - -
- - ----------------------------------------------------------------------
Issue:
======
Frames are used in Internet Explorer to provide for a fuller
browsing experience. By design, scripts in the frame of one site or
domain should be prohibited from accessing the content of frames
in another site or domain. However, a flaw exists in how VBScript
is handled in IE relating to validating cross-domain access. This
flaw can allow scripts of one domain to access the contents of
another domain in a frame.
A malicious user could exploit this vulnerability by using
scripting to extract the contents of frames in other domains,
then sending that content back to their web site. This would
enable the attacker to view files on the user's local machine
or capture the contents of third-party web sites the user visited
after leaving the attacker's site. The latter scenario could,
in the worst case, enable the attacker to learn personal
information like user names, passwords, or credit card information.
In both cases, the user would either have to go to a site under
the attacker's control or view an HTML email sent by the attacker.
In addition, the attacker would have to know the exact name and
location of any files on the user's system. Further, the attacker
could only gain access to files that can be displayed in a browser
window, such as text files, HTML files, or image files.
Mitigating Factors:
====================
- The vulnerability could only be used to view files. It could not
be used to create, delete, modify or execute them.
- The vulnerability would only allow an attacker to read files that
can be opened in a browser window, such as image files, HTML
files and text files. Other file types, such as binary files,
executable files, Word documents, and so forth, could not be read.
- The attacker would need to specify the exact name and location of
the file in order to read it.
- The email-borne attack scenario would be blocked if the user were
using any of the following: Outlook 98 or 2000 with the Outlook
Email Security Update installed; Outlook 2002; or Outlook
Express 6.
Risk Rating:
============
- Internet systems: Moderate
- Intranet systems: Moderate
- Client systems: Critical
Patch Availability:
===================
- A patch is available to fix this vulnerability. Please read the
Security Bulletin at
http://www.microsoft.com/technet/security/bulletin/ms02-009.asp
for information on obtaining this patch.
Acknowledgment:
===============
- Zentai Peter Aron, Ivy Hungary Ltd (http://w3.ivy.hu/)
- - -
- - ---------------------------------------------------------------------
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
iQEVAwUBPHWQ240ZSRQxA/UrAQGVgQf/YHikbABgDGo3VsxZb362rYOKjKpk3Yfl
o5BH8quzonHYlASh/vRRcys1PtMaVwxdNbDu9DCL2Adg4gDdBrID/Aet3J+f1lgB
rtKS9SNxwUAd7nht5FX/4SQYXcFlh9oKtr+e6uXZkgED/4TdoTR0JvDOkTh7hvFR
u4N0eLwRFmgApuftEqaLh3vzxR4V5RoREXDsaJLZLc191MnULFIk4iIASdIIxWiE
6YJfukAXSlvpWMQolGcEbqinUEHAztCrYpS4Rp5BYeNV3MZWLqkRf7zMu23KTUMi
rhC+NXtRd2AYM255o0NFn2nlxzBVfc/d7P/GG5BvPTjOQcfLJzZIdg==
=qlLh
- -----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
iQCVAwUBPHZMAyh9+71yA2DNAQEyyQP/cEx9pD6Oq75opioCFEPugMzid0oxI2mF
9GU2TKaWMbe8wJyxvAGC+EjVDnrfSSPsaQIwWPiooXgDDll3v8w86BY6NBOpilx5
Zspydkf9temTP89kc2wfHg9z47X2V8NcE4AFpulK+zxBRMYTBN6MYO/gvpIcjaim
ACWYvo4FiiI=
=t6iM
-----END PGP SIGNATURE-----