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              AUSCERT External Security Bulletin Redistribution

                             
                     ESB-97.078 -- CIAC Bulletin H-76
	        Netscape Navigator Security Vulnerability
                               1 July 1997

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

The U.S. Department of Energy Computer Incident Advisory Capability has
released the following advisory concerning a vulnerability in Netscape
Navigator.  This vulnerability may allow a Web site operator to retrieve
known files from the hard discs of visiting users.

The following security bulletin is provided as a service to AUSCERT's
members.  As AUSCERT did not write this document, AUSCERT has had no
control over its content.  As such, 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.

Contact information for CIAC is included in the Security Bulletin
below.  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 4477
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.


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[   For Public Release   ]
             __________________________________________________________

                       The U.S. Department of Energy
                    Computer Incident Advisory Capability
                           ___  __ __    _     ___
                          /       |     /_   /
                          \___  __|__  /     \___
             __________________________________________________________

                             INFORMATION BULLETIN

                   Netscape Navigator Security Vulnerability

June 26, 1997 17:00 GMT                                            Number H-76
______________________________________________________________________________
PROBLEM:       A problem has been identified in the Netscape Navigator.
PLATFORM:      All platforms running Netscape Navigator 2.0, 3.0, and
               Communicator 4.0.
DAMAGE:        This vulnerability may allow a Web site operator to retrieve
               known files from the hard disks of visiting users by mimicking
               the submission of a form.
SOLUTION:      Apply the workaround or the appropriate patch provided below.
______________________________________________________________________________
VULNERABILITY  The exploit is not currently available but knownledge of this
ASSESSMENT:    vulnerability has been highly publicized by the media.
______________________________________________________________________________

Introduction
============

Recently, the Internet community was made aware of a bug in the Netscape
Navigator. Netscape engineers were able to recreated the bug in Netscape
Communicator and Navigator 2.0 and 3.0.

Known as the privacy bug, it may allow a Web site operator to retrieve known
files from the hard disks of visiting users by mimicking the submission of a
form. Under ordinary circumstances, users browsing on known, trusted sites
are not at risk. However, if a user visits an unknown, untrusted site, the
operator of that site could potentially retrieve files from a user's hard disk
through an obscure series of steps. To access a file on the hard drive the
Web site operator would need to know the exact name and location of the file.
Even though the bug has been highly publicized, this factor in itself limits
the possibility of this vulnerability being exploited.

Netscape released the following statement: "The execution of this attack
requires specific knowledge of the user's machine to cause harm and so is
unlikely to be reproduced. Because this specific bug has existed for more
than a year and a half since Navigator 2.0 -- and Netscape has never had a
report about this bug or any loss based on this bug -- we believe the risk
to users from this bug is relatively low." 

CIAC recommends that you apply the workarounds or the appropriate patch
provided below.     

Workarounds
===========

To remove any risk of this bug, Navigator users should download
the updated version of Communicator or Navigator, that includes the fix.
In the interim, users of Navigator 3.0 and Communicator 4.0 can take the
following steps to enable warning dialog boxes to detect and cancel form
submissions:

   In Navigator 3.0: Go to the Options menu and select Security
                     Preferences. Select the "Submitting a Form
                     Insecurely" preference to enable that warning
                     dialog box.

   In Navigator 4.0: Select the lock in the toolbar to open the
                     Security Advisor. Select Navigator, then select
                     the "Sending Unencrypted Information to a Site"
                     preference to enable that warning dialog box.

Patches or Upgrades
===================
     
   Communicator 4.01 for Windows (includes the fix for privacy bug)
      http://home.netscape.com/download/client_download.html?communicator4.01

   Navigator 3.0
      Fix pending per Netscape


______________________________________________________________________________

CIAC wishes to acknowledge the contributions of Netscape 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:    +1 510-422-8193
    FAX:      +1 510-423-8002
    STU-III:  +1 510-423-2604
    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), call the CIAC voice number 510-422-8193 and leave a message,
or call 800-759-7243 (800-SKY-PAGE) to send a Sky Page. CIAC has two
Sky Page PIN numbers, the primary PIN number, 8550070, is for the CIAC
duty person, and the secondary PIN number, 8550074 is 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://ciac.llnl.gov/
   Anonymous FTP:       ciac.llnl.gov (198.128.39.53)
   Modem access:        +1 (510) 423-4753 (28.8K baud)
                        +1 (510) 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. CIAC-NOTES for Notes, a collection of computer security articles;
3. SPI-ANNOUNCE for official news about Security Profile Inspector
   (SPI) software updates, new features, distribution and
   availability;
4. 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, ciac-notes, spi-announce OR spi-notes for list-name:

E-mail to       ciac-listproc@llnl.gov or majordomo@tholia.llnl.gov:
        subscribe list-name
  e.g., subscribe ciac-notes

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)

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H-75: Solaris Solstice AdminSuite Vulnerabilities

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