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Cisco PIX Firewall Manager File Exposure

Advisory ID: cisco-sa-19980902-pix-mgr-file

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-19980902-pix-mgr-file

Revision 1.0

For Public Release 1998 September 2 17:00  UTC (GMT)


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.

This advisory is posted at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-19980902-pix-mgr-file.

Affected Products

This section provides details on affected products.

Vulnerable Products

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.

Products Confirmed Not Vulnerable

No other Cisco products are currently known to be affected by these vulnerabilities.

Details

This vulnerability has been assigned Cisco Bug ID CSCdk39378.

Vulnerability Scoring Details

Cisco has provided scores for the vulnerabilities in this advisory based on the Common Vulnerability Scoring System (CVSS). The CVSS scoring in this Security Advisory is done in accordance with CVSS version 2.0.

CVSS is a standards-based scoring method that conveys vulnerability severity and helps determine urgency and priority of response.

Cisco has provided a base and temporal score. Customers can then compute environmental scores to assist in determining the impact of the vulnerability in individual networks.

Cisco has provided an FAQ to answer additional questions regarding CVSS at
http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html .

Cisco has also provided a CVSS calculator to help compute the environmental impact for individual networks at
http://intellishield.cisco.com/security/alertmanager/cvss .


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.

Software Versions and Fixes

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.

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.

Obtaining Fixed Software

Cisco has made free software available to address this vulnerability for affected customers. Prior to deploying software, customers should consult their maintenance provider or check the software for feature set compatibility and known issues specific to their environment.

Customers may only install and expect support for the feature sets they have purchased. By installing, downloading, accessing or otherwise using such software upgrades, customers agree to be bound by the terms of Cisco's software license terms found at http://www.cisco.com/public/sw-license-agreement.html, or as otherwise set forth at Cisco.com Downloads at http://www.cisco.com/public/sw-center/sw-usingswc.shtml.

Do not contact either "psirt@cisco.com" or "security-alert@cisco.com" for software upgrades.

Customers with Service Contracts

Customers with contracts should obtain upgraded software through their regular update channels. For most customers, this means that upgrades should be obtained through the Software Center on Cisco's worldwide website at http://www.cisco.com.

Customers using Third Party Support Organizations

Customers whose Cisco products are provided or maintained through prior or existing agreement with third-party support organizations such as Cisco Partners, authorized resellers, or service providers should contact that support organization for guidance and assistance with the appropriate course of action in regards to this advisory.

The effectiveness of any workaround or fix is dependent on specific customer situations such as product mix, network topology, traffic behavior, and organizational mission. Due to the variety of affected products and releases, customers should consult with their service provider or support organization to ensure any applied workaround or fix is the most appropriate for use in the intended network before it is deployed.

Customers without Service Contracts

Customers who purchase direct from Cisco but who do not hold a Cisco service contract and customers who purchase through third-party vendors but are unsuccessful at obtaining fixed software through their point of sale should get their upgrades by contacting the Cisco Technical Assistance Center (TAC). TAC contacts 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: tac@cisco.com

Have your product serial number available and give the URL of this notice as evidence of your entitlement to a free upgrade. Free upgrades for non-contract customers must be requested through the TAC.

Refer to http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml for additional TAC contact information, including special localized telephone numbers and instructions and e-mail addresses for use in various languages.

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 "bugtraq@netspace.org" 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: Final

THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.

A stand-alone copy or Paraphrase of the text of this document that omits the distribution URL in the following section is an uncontrolled copy, and may lack important information or contain factual errors.


Distribution

This notice will be posted on Cisco's Worldwide Web server at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-19980902-pix-mgr-file. In addition to Worldwide Web posting, the initial version of this notice is being sent to the following e-mail and Usenet news recipients:

  • cust-security-announce@cisco.com
  • bugtraq@netspace.org
  • first-teams@first.org (includes CERT/CC)
  • cisco@spot.colorado.edu
  • comp.dcom.sys.cisco
  • first-info@first.org
  • Various internal Cisco mailing lists

Future updates of this advisory, 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 above URL for any updates.


Revision History

Revision 1.0

1998-September-02

Initial released version

Cisco Security Procedures

Please report security issues with Cisco products, and/or sensitive security intrusion emergencies involving Cisco products, to security-alert@cisco.com. Reports may be encrypted using PGP; public RSA and DSS keys for "security-alert@cisco.com" are on the public PGP keyservers.

The alias "security-alert@cisco.com" 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 "security-alert@cisco.com".

Please do not use "security-alert@cisco.com" 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: tac@cisco.com

All formal public security notices generated by Cisco are sent to the public mailing list "cust-security-announce@cisco.com". For information on subscribing to this mailing list, send a message containing the single line "info cust-security-announce" to "majordomo@cisco.com". An analogous list, "cust-security-discuss@cisco.com" is available for public discussion of the notices and of other Cisco security issues.