Date: Wed, 2 Sep 1998 17:55:43 -0000
From: [email protected]
To: [email protected]Subject: Cisco Security Notice: PIX Firewall Manager File Exposure
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Field Notice:
Cisco PIX Firewall Manager File Exposure
Revision 1.0
For release 10:00 AM US/Pacific, Wednesday, September 2, 1998
Cisco internal use only until release date.
Summary
=======
The Cisco PIX Firewall product is shipped with a management application
known as PIX Firewall Manager, or PFM. PFM is a Worldwide-Web-based
application, and includes a limited HTTP server. The PFM HTTP server runs on
Windows NT computers. A vulnerability in the PFM HTTP server allows any
attacker who can connect to the server to retrieve any file known in advance
to exist on the Windows NT host. In almost all cases, this means that the
host is vulnerable to attack by any user inside the firewall, but not by
users outside the firewall.
This vulnerability was discovered and reported by Brett M. Oliphant, Manager
of Corporate Computer Security at Lafayette Life Insurance Company.
Who Is Affected
===============
If you are running Cisco PIX Firewall Manager software for Windows NT, as
shipped with PIX Firewall versions up to and including 4.2(1), and if
untrusted users can make TCP connections to port 8080 on your PFM server,
you are affected by this vulnerability. No other Cisco products are
affected.
Impact
======
To exploit this vulnerability, attackers must be able to make TCP
connections to port 8080 on the NT host on which you have installed PFM. In
all recommended configurations and in the overwhelming majority of actual
installations, port 8080 of the PFM host can be reached only from inside the
PIX Firewall, not from the outside.
In addition, attackers must know or discover the names and locations of the
files they wish to read. This vulnerability does not permit "browsing" of
the NT host or reading of directories; attackers must know where the target
file is, or must make repeated attempts at guessing the location until the
target file is found.
If they can meet these prerequisites, attackers can retrieve any file or
files on the NT host on which PFM is installed, as well as any file or files
on network servers accessible through that host's file system. All files
readable to the "administrator" account are affected. In most cases, this
includes all files on the local disk, and many or most files on
network-mounted volumes. In addition to obtaining confidential information
directly, attackers may be able to use information obtained from the
retrieved files to help them to conduct other attacks against the NT host.
This vulnerability can be exploited using ordinary tools available on most
networked computer systems. There is no need for a special exploitation
program, nor is there a need for any unusual technical skill. Although Cisco
will not release further details of how to exploit this vulnerability, we
believe that they could quickly be guessed at, based on the contents of this
advisory alone, by any person minimally sophisticated in such matters, and
we anticipate that other parties will publish these details shortly after
the release of this notice.
Details
=======
This vulnerability has been assigned Cisco Bug ID CSCdk39378.
Affected and Repaired Software Versions
- -------------------------------------
This vulnerability affects all releases of Cisco PIX Firewall Manager up to,
and including, release 4.2(1). 4.2(2) beta releases are also affected. Fixed
versions are available for both 4.1-based and 4.2-based versions of PFM.
The fixed version for 4.1 is 4.1( 6b). To use PFM version 4.1(6b), you must
install software version 4.1(6) on the PIX Firewall itself.
The fixed version for 4.2 is 4.2(2), which will be released along with
4.2(2) software for the PIX Firewall itself. 4.2(1) PIX Firewall software is
under line stop because of software quality issues, and is not recommended
for use or installation. Therefore, there will be no PFM fix for 4.2(1) PIX
Firewall software. Customers who are using 4.2(1) are advised to downgrade
to version 4.1(6) on their PIX Firewalls, and to install PFM 4.1(6b). If
this is not possible, customers should use the workarounds listed below.
All releases subsequent to these repaired releases will also include the
fix. There will be no future vulnerable PFM releases.
Getting Fixed Software
- ----
Cisco is offering free software upgrades for this problem to all customers
who are using PFM, regardless of contract status. This free upgrade program
includes both PFM version 4.1(6b) and, if necessary, the corresponding PIX
Firewall software version 4.1(6).
If you have a service contract, please download the new software from
Cisco's Worldwide Web site at http://www.cisco.com. If you do not have a
service contract, please call the Cisco TAC at one of the telephone numbers
listed in the "Cisco Security Procedures" section of this notice. Give the
URL of this notice as evidence of your entitlement to an upgrade.
Workarounds
- ---------
Because a software fix is available, Cisco believes that the best response
for the vast majority of customers is to upgrade to repaired software. These
workarounds are offered only for customers who are unable to upgrade for
unusual reasons.
We believe that many customers have installed the PIX Firewall Manager
product on their NT workstations, but have finalized their PIX Firewall
configurations and are no longer actively using PFM. The most effective
workaround for these customers is simply to uninstall PFM, and to reinstall
a repaired version later if necessary.
Another possible workaround is to use firewall devices, such as the PIX
Firewall itself, to prevent untrusted users from making connections to port
8080 on the NT host on which PFM in installed. Depending on the customer
configuration, it may be desirable to move the NT host to the PIX Firewall's
DMZ network to prevent access by unauthorized inside users; the security of
the other systems on the DMZ network should be carefully considered in
making this decision.
It is not possible to stop the PFM HTTP server from using the NT
"administrator" account.
Exploitation and Public Announcements
Cisco has had no reports of malicious exploitation of this vulnerability.
However, such exploitation may reasonably be expected to begin in the near
future.
The existence of this vulnerability was publicly announced on the
"[email protected]" mailing list on Monday, August 31, 1998, and should
be considered to be widely known to exist. Exploitation details were not
given.
Status of This Notice
This is a final field notice. Although Cisco cannot guarantee the accuracy
of all statements in this notice, all the facts have been checked to the
best of our ability. Cisco does not anticipate issuing updated versions of
this notice unless there is some material change in the facts. Should there
be a significant change in the facts, Cisco may update this notice.
Distribution
- ----------
This notice will be posted on Cisco's Worldwide Web site at
http://www.cisco.com/warp/public/770/pixmgrfile-pub.shtml. In addition to
Worldwide Web posting, the initial version of this notice is being sent to
the following e-mail and Usenet news recipients:
* [email protected]
* [email protected]
* [email protected] (includes CERT/CC)
* [email protected]
* comp.dcom.sys.cisco
* [email protected]
* Various internal Cisco mailing lists
Future updates of this notice, if any, will be placed on Cisco's Worldwide
Web server, but may or may not be actively announced on mailing lists or
newsgroups. Users concerned about this problem are encouraged to check the
URL given above for any updates.
Revision History
- --------------
Revision 0.1, Initial released version
09:30 AM
US/Pacific,
02-SEP-1998
Cisco Security Procedures
Please report security issues with Cisco products, and/or sensitive security
intrusion emergencies involving Cisco products, to [email protected].
Reports may be encrypted using PGP; public RSA and DSS keys for
"[email protected]" are on the public PGP keyservers.
The alias "[email protected]" is used only for reports incoming to
Cisco. Mail sent to the list goes only to a very small group of users within
Cisco. Neither outside users nor unauthorized Cisco employees may subscribe
to "[email protected]".
Please do not use "[email protected]" for configuration questions,
for security intrusions that you do not consider to be sensitive
emergencies, or for general, non-security-related support requests. We do
not have the capacity to handle such requests through this channel, and will
refer them to the TAC, delaying response to your questions. We advise
contacting the TAC directly with these requests. TAC contact numbers are as
follows:
* +1 800 553 2447 (toll-free from within North America)
* +1 408 526 7209 (toll call from anywhere in the world)
* e-mail: [email protected]
All formal public security notices generated by Cisco are sent to the public
mailing list "[email protected]". For information on
subscribing to this mailing list, send a message containing the single line
"info cust-security-announce" to "[email protected]". An analogous list,
"[email protected]" is available for public discussion of the
notices and of other Cisco security issues.
This notice is copyright 1998 by Cisco Systems, Inc. This notice may be
redistributed freely after the release date given at the top of the notice,
provided that redistributed copies are complete and unmodified, including
all date and version information.
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