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Subject: FileMaker Pro network protocol sends passwords to any client
attempting to connect to a shared database.


Date:        8 April 2003
Author:      Stephen White <swhite+fmbug@ox.compsoc.net>
Application: FileMaker Pro, FileMaker Server
Vendor:      FileMaker Inc. http://www.filemaker.com/
Versions:    5.0, 5.5, 6.0.  All platforms.
             verified on FileMaker Pro 5.0/Windows 2000,
                         FileMaker Pro 6.0/Windows 2000,
                         FileMaker Server 5.5/Linux.
Bug:         Remotely obtain passwords - clients connecting via TCP/IP are sent              complete list of database passwords.
Remote:      Yes.
Local:       It is already known that local users can obtain database passwords,
             eg. software from http://www.lostpassword.com/filemaker.htm

Overview
- --------

Vulnerable organisations: those using FileMaker Pro TCP/IP network sharing
(including FileMaker Server).

Impact: Having obtained a list of passwords for a given database an attacker
could use them to either read or modify the potentially sensitive data
contained in the database.  If, against best practises, the same passwords are
used elsewhere within the organisation an attacker could use them as a basis
for attacking other systems.

Fix / Workaround
- ----------------

FileMaker were contacted about this issue on the March 8, 2003.  FileMaker have
stated that they intend to fix this issue for their next release, they have not
stated when this next release will be.  They do not appear to intend to produce
an update or fix for current releases.

Solutions:

* Disable 'multi user' or 'TCP/IP' access to FileMaker databases.
* If sharing via FileMaker networking (peer-to-peer or client/server) is
  required ensure that FileMaker Pro hosts and servers are only accessible
  to trusted intra-net systems through an appropriate Firewall setup.
  External access could be arranged by using VPN or TCP tunnelling software.
* Share data using alternative means, such as web publishing with 'Web
  Companion' or Lasso, or other middleware or 3rd party plug-ins.  I have not
  tested these so am not in a position to provide specific recommendations
* Use alternative database software if these solutions do not address your
  requirements.

Discussion
- ----------

FileMaker Pro communicates with servers or multi user databases shared via
TCP/IP using a proprietary network protocol.  A full analysis of this protocol
is not possible due to it's proprietary nature, however it appears that the
server exploits the proprietary nature of the protocol by trusting the client
to carry out tasks such as validating passwords.  In the course of the network
communication the server will send the client the list of obscured passwords.
The client will then prompt the user to enter a password, which is checked
against this list before continuing - a classic example of 'Security by
Obscurity'.

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