__________________________________________________________
The U.S. Department of Energy
Computer Incident Advisory Capability
___ __ __ _ ___
/ | /_\ /
\___ __|__ / \ \___
__________________________________________________________
INFORMATION BULLETIN
Microsoft IE 5 Vulnerability - "download behavior"
October 13, 1999 17:00 GMT Number K-002
______________________________________________________________________________
PROBLEM: A security vulnerability in Microsoft Internet Explorer 5
may allow a malicious web site operator to read files on the
computer of a person who visited the site.
PLATFORM: Microsoft Windows 95/98 and NT running Internet Explorer 5
DAMAGE: A malicious web site operator may read files on a computer
visiting their site. The vulnerability would not allow files to
be created, deleted or modified.
SOLUTION: Load the Hotfix.
______________________________________________________________________________
VULNERABILITY The risk is low. A user would have to visit a web site and view
ASSESSMENT: a web page constructed to exploit this vulnerability.
______________________________________________________________________________
[ Start Microsoft Advisory ]
Microsoft Security Bulletin (MS99-040)
--------------------------------------
Patch Available for "Download Behavior" Vulnerability
Originally Posted: September 28, 1999
Updated: October 08, 1999
Summary
=======
On September 28, 1999, Microsoft released the original version of this
bulletin, in order to provide a workaround for a security vulnerability in
Microsoft(r) Internet Explorer 5 that could allow a malicious web site
operator to read files on the computer of a person who visited the site.
Microsoft has completed a patch that completely eliminates the
vulnerability, and has re-released this bulletin in order to advise
customers of its availability.
Frequently asked questions regarding this vulnerability can be found
at http://www.microsoft.com/security/bulletins/MS99-040faq.asp.
Issue
=====
IE 5 includes a feature called "download behavior" that allows web page
authors to download files for use in client-side script. By design, a web
site should only be able to download files that reside in its domain; this
prevents client-side code from exposing files on the user's machine or
local intranet to the web site. However, a server-side redirect can be used
to bypass this restriction, thereby enabling a malicious web site operator
to read files on the user's machine or the user's local intranet. This
vulnerability would chiefly affect workstations that are connected to the
Internet.
Affected Software Versions
==========================
- Microsoft Internet Explorer 5
Patch Availability
==================
The patch is available for download at either of the following locations
- http://windowsupdate.microsoft.com
- http://www.microsoft.com/msdownload/iebuild/dlbhav/en/dlbhav.htm
More Information
================
Please see the following references for more information related to this
issue.
- Microsoft Security Bulletin MS99-040: Frequently Asked Questions,
http://www.microsoft.com/security/bulletins/ms99-040faq.asp.
- Microsoft Knowledge Base (KB) article Q242542,
"Download Behavior" Vulnerability in Internet Explorer 5,
http://support.microsoft.com/support/kb/articles/Q242/5/42.asp.
(Note: It may take 24 hours from the original posting of this
bulletin for this KB article to be visible.)
- Microsoft Security Advisor web site,
http://www.microsoft.com/security/default.asp.
Obtaining Support on this Issue
===============================
Information on contacting Microsoft Technical Support is available
at http://support.microsoft.com/support/contact/default.asp.
Acknowledgments
===============
Microsoft acknowledges Georgi Guninski for bringing this issue to our
attention.
Revisions
=========
- September 28, 1999: Bulletin Created.
- October 08, 1999: Bulletin updated to announce availability of patch.
-----------------------------------------------------------------------
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.
(c) 1999 Microsoft Corporation. All rights reserved. Terms of Use.
*******************************************************************
You have received this e-mail bulletin as a result of your registration
to the Microsoft Product Security Notification Service. You may
unsubscribe from this e-mail notification service at any time by sending
an e-mail to MICROSOFT_SECURITY-SIGNOFF-REQUEST@ANNOUNCE.MICROSOFT.COM
The subject line and message body are not used in processing the request,
and can be anything you like.
For more information on the Microsoft Security Notification Service
please visit http://www.microsoft.com/security/services/bulletin.asp. For
security-related information about Microsoft products, please visit the
Microsoft Security Advisor web site at http://www.microsoft.com/security.
[ End Microsoft Advisory ]
______________________________________________________________________________
CIAC wishes to acknowledge the contributions of Microsoft for the
information contained in this bulletin.
______________________________________________________________________________
CIAC, the Computer Incident Advisory Capability, is the computer
security incident response team for the U.S. Department of Energy
(DOE) and the emergency backup response team for the National
Institutes of Health (NIH). CIAC is located at the Lawrence Livermore
National Laboratory in Livermore, California. CIAC is also a founding
member of FIRST, the Forum of Incident Response and Security Teams, a
global organization established to foster cooperation and coordination
among computer security teams worldwide.
CIAC services are available to DOE, DOE contractors, and the NIH. CIAC
can be contacted at:
Voice: +1 925-422-8193
FAX: +1 925-423-8002
STU-III: +1 925-423-2604
E-mail: ciac@llnl.gov
For emergencies and off-hour assistance, DOE, DOE contractor sites,
and the NIH may contact CIAC 24-hours a day. During off hours (5PM -
8AM PST), use one of the following methods to contact CIAC:
1. Call the CIAC voice number 925-422-8193 and leave a message, or
2. Call 888-449-8369 to send a Sky Page to the CIAC duty person or
3. Send e-mail to 4498369@skytel.com, or
4. Call 800-201-9288 for the CIAC Project Leader.
Previous CIAC notices, anti-virus software, and other information are
available from the CIAC Computer Security Archive.
World Wide Web: http://www.ciac.org/
(or http://ciac.llnl.gov -- they're the same machine)
Anonymous FTP: ftp.ciac.org
(or ciac.llnl.gov -- they're the same machine)
Modem access: +1 (925) 423-4753 (28.8K baud)
+1 (925) 423-3331 (28.8K baud)
CIAC has several self-subscribing mailing lists for electronic
publications:
1. CIAC-BULLETIN for Advisories, highest priority - time critical
information and Bulletins, important computer security information;
2. SPI-ANNOUNCE for official news about Security Profile Inspector
(SPI) software updates, new features, distribution and
availability;
3. SPI-NOTES, for discussion of problems and solutions regarding the
use of SPI products.
Our mailing lists are managed by a public domain software package
called Majordomo, which ignores E-mail header subject lines. To
subscribe (add yourself) to one of our mailing lists, send the
following request as the E-mail message body, substituting
ciac-bulletin, spi-announce OR spi-notes for list-name:
E-mail to ciac-listproc@llnl.gov or majordomo@rumpole.llnl.gov:
subscribe list-name
e.g., subscribe ciac-bulletin
You will receive an acknowledgment email immediately with a confirmation
that you will need to mail back to the addresses above, as per the
instructions in the email. This is a partial protection to make sure
you are really the one who asked to be signed up for the list in question.
If you include the word 'help' in the body of an email to the above address,
it will also send back an information file on how to subscribe/unsubscribe,
get past issues of CIAC bulletins via email, etc.
PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing
communities receive CIAC bulletins. If you are not part of these
communities, please contact your agency's response team to report
incidents. Your agency's team will coordinate with CIAC. The Forum of
Incident Response and Security Teams (FIRST) is a world-wide
organization. A list of FIRST member organizations and their
constituencies can be obtained via WWW at http://www.first.org/.
This document was prepared as an account of work sponsored by an
agency of the United States Government. Neither the United States
Government nor the University of California nor any of their
employees, makes any warranty, express or implied, or assumes any
legal liability or responsibility for the accuracy, completeness, or
usefulness of any information, apparatus, product, or process
disclosed, or represents that its use would not infringe privately
owned rights. Reference herein to any specific commercial products,
process, or service by trade name, trademark, manufacturer, or
otherwise, does not necessarily constitute or imply its endorsement,
recommendation or favoring by the United States Government or the
University of California. The views and opinions of authors expressed
herein do not necessarily state or reflect those of the United States
Government or the University of California, and shall not be used for
advertising or product endorsement purposes.
LAST 10 CIAC BULLETINS ISSUED (Previous bulletins available from CIAC)
J-064: ActiveX Controls, Scriptlet.typlib & Eyedog, Vulnerabilities
J-065: Wu-ftpd Vulnerability
J-066: FreeBSD File Flags and Main-In-The-Middle Attack
J-067: Profiling Across FreeBSD Exec Calls
J-068: FreeBSD Vulnerabilities in wu-ftpd and proftpd
J-069: SunOS LC MESSAGES Environment Variable Vulnerability
J-070: Microsoft Windows 95 and 98 Telnet Client Vulnerability
J-071: Buffer Overflow Vulnerability in amd
J-072: IBM AIX Buffer Overflow Vulnerability
K-001: Four Vulnerabilities in the Common Desktop Environment
TUCoPS is optimized to look best in Firefox® on a widescreen monitor (1440x900 or better).
Site design & layout copyright © 1986-2024 AOH
