Cisco Security Advisory
Click Icon to Copy Verbose Score
AV:R/AC:H/Au:NR/C:P/I:P/A:P/B:N/E:F/RL:W/RC:C
-
Versions of Cisco Network Services (CNS) NetFlow Collection Engine (NFC) prior to 6.0 create and use default accounts with identical usernames and passwords. An attacker with knowledge of these accounts can modify the application configuration and, in certain instances, gain user access to the host operating system.
The upgrade to NFC version 6.0 is not a free upgrade. This default password issue does not require a software upgrade and can be changed by a configuration command for all affected customers. The workaround detailed in this document demonstrates how to change the passwords in 5.0.
This advisory is posted at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20070425-nfc.
-
Vulnerable Products
This vulnerability affects Cisco NetFlow Collection Engine running software versions prior to 6.0.0. The software version of the Cisco NetFlow Collection Engine can be determined by either logging into the web-based user interface (UI) or using the show-tech parameter of the nfcollector command from the host operating system. For customers running version 6.0 or later, the nfcollector command uses the version parameter to determine the software level.
Users can determine the NFC version by using a web browser to navigate to http://<nfc-hostname>:8080/nfc in a web browser and selecting About in the upper left-hand corner. The browser displays the NFC version in a new window.
The NFC version can be determined from the host operating system by using the show-tech parameter of the /opt/CSCOnfc/nfcollector command. On systems running NFC version 5.0.3, the output from /opt/CSCOnfc/bin/nfcollector show-tech should display a result similar to the following:
$ /opt/CSCOnfc/nfcollector show-tech ********** pkginfo/swlist ********** Name : CSCOnfc Relocations: /opt/CSCOnfc Version : 5.0.3 Vendor: Cisco Systems, Inc Release : 2 Build Date: Wed 06 Sep 2006 11:19:59 AM EDT Install Date: Mon 12 Feb 2007 04:26:54 PM EST Build Host: nfc-hpux.cisco.com Group : Applications/Network Source RPM: CSCOnfc-5.0.3-2.src.rpm Size : 109385602 License: Copyright (c) 2002-2003 by Cisco Systems, Inc. Signature : (none) URL : http://www.cisco.com Summary : Cisco NetFlow Collector Description : Cisco CNS NetFlow Collection Engine receives, filters, and aggregates NetFlow traffic data generated by Cisco routers and switches.
Products Confirmed Not Vulnerable
No other Cisco products are known to be vulnerable to the issues described in this advisory.
-
Cisco CNS NetFlow Collection Engine is used to collect and monitor NetFlow accounting data for devices that support NetFlow, such as routers and switches. This data can be used to provide a network baseline, against which irregular activities like denial of service (DoS) attacks, worms, and other malicious activity can be more easily detected.
NFC is installed on a supported UNIX platform. The installation creates a default web based user account, nfcuser, which is required to perform application maintenance, configuration, and troubleshooting with a password of nfcuser. In versions prior to 6.0, the Linux installer will also create a local user, also nfcuser, on the operating system with a default password also identical to the username. If the user already exists, the Linux installer will change the password to be the same as the username.
This issue is documented in Cisco Bug ID CSCsh75038 ( registered customers only)
Vulnerability Scoring Details
Cisco is providing scores for the vulnerabilities in this advisory based on the Common Vulnerability Scoring System (CVSS).
Cisco will provide a base and temporal score. Customers can then compute environmental scores to assist in determining the impact of the vulnerability in individual networks.
Cisco PSIRT will set the bias in all cases to normal. Customers are encouraged to apply the bias parameter when determining the environmental impact of a particular vulnerability.
CVSS is a standards based scoring method that conveys vulnerability severity and helps determine urgency and priority of response.
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
https://sec.cloudapps.cisco.com/security/center/cvssCalculator.x .
CSCsh75038 - Default password for nfcuser in NFC
Calculate the environmental score of CSCsh75038
CVSS Base Score - 5.6
Access Vector
Access Complexity
Authentication
Confidentiality Impact
Integrity Impact
Availability Impact
Impact Bias
Remote
High
Not Required
Partial
Partial
Partial
Normal
CVSS Temporal Score - 5.1
Exploitability
Remediation Level
Report Confidence
Functional
Workaround
Confirmed
-
This issue has been addressed starting in release 6.0 by prompting the user to change the password for the web based nfcuser account during the application installation or during an upgrade to a version later than 6.0 as shown in the following example. This only applies to the web user and password, on Linux hosts, the nfcuser on the host operating system needs to be manually changed as shown at the end of the workarounds section. Installations on Solaris have always required the local nfcuser to be created before the installation and therefore only the web based user account is affected by this advisory. NFC installations for version 6.0 and later on Solaris and Linux require the nfcuser account to be created on the host operating system before the installer is run.
For all installations of NFC versions prior to 6.0, the web user can be changed using the following procedure:
Edit the file authentication parameters stored in ${NFC_DIR}/config/auth.config, as shown below. The nfc-user field can be changed and a strong password should be chosen for the nfc-password.
NFC { com.cisco.nfc.collector.web.auth.SimpleLoginModule required nfc-user="nfcuser" nfc-password="nfcuser"; };Then as the nfcuser, stop and restart the NFC applications. This is done using the nfcollector command, as shown in the following example:
# su - nfcuser $ /opt/CSCOnfc/bin/nfcollector stop all nfcxml: Not Running collection: Not Running re: Not Running; autostart not configured web: Not Running $ /opt/CSCOnfc/bin/nfcollector start all This product contains cryptographic features and is subject to United States and local country laws governing import, export, transfer and use. Delivery of Cisco cryptographic products does not imply third-party authority to import, export, distribute or use encryption. Importers, exporters, distributors and users are responsible for compliance with U.S. and local country laws. By using this product you agree to comply with applicable laws and regulations. If you are unable to comply with U.S. and local laws, return this product immediately. A summary of U.S. laws governing Cisco cryptographic products may be found at: http://www.cisco.com/wwl/export/crypto/tool/stqrg.html If you require further assistance please contact us by sending email to export@cisco.com. nfcxml: Running (pid: 6598) collection: Running (pid: 6606) re: Not Running; autostart not configured web: Running (pid: 6618)
Additionally, on Linux installations of NFC prior to version 6.0, use the passwd command to change the nfcuser password, as shown in the following example:
# passwd nfcuser Changing password for user nfcuser. New UNIX password: Retype new UNIX password: passwd: all authentication tokens updated successfully.
Please note that the local user password does not have to match the password of the web user account. Upgrading to version 6.0 will automatically prompt the administrator for a new nfcuser password to be used in the UI. The nfcuser password for the host operating system should still be changed as described above.
-
When considering software upgrades, also consult http://www.cisco.com/go/psirt and any subsequent advisories to determine exposure and a complete upgrade solution.
In all cases, customers should exercise caution to be certain the devices to be upgraded contain sufficient memory and that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, contact the Cisco Technical Assistance Center ("TAC") or your contracted maintenance provider for assistance.
-
The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory.
-
To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
-
Show Less
Revision 1.1
2008-April-24
Updated the link to the CSCsh75038 CVSS score.
Revision 1.0
2007-April-25
Initial public release
-
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 is an uncontrolled copy, and may lack important information or contain factual errors. The information in this document is intended for end-users of Cisco products.