Cisco Security Advisory

Vulnerable Products

Products Confirmed Not Vulnerable

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)

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

http://intellishield.cisco.com/security/alertmanager/cvss .

Successful exploitation of the vulnerability may result in full administrative control of the NetFlow Collection Engine and user-level access to the host operating system.

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.

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.

Cisco will not make free upgrade software available to address this vulnerability for affected customers. The workaround described in this document describes how to change the passwords in current releases of the software. This advisory will be updated as fixed software becomes available. 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.

The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory.

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.

This advisory is posted on Cisco's worldwide website at :

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20070425-nfc

In addition to worldwide web posting, a text version of this notice is clear-signed with the Cisco PSIRT PGP key and is posted to the following e-mail and Usenet news recipients.

• cust-security-announce@cisco.com
  
• first-teams@first.org
  
• bugtraq@securityfocus.com
  
• vulnwatch@vulnwatch.org
  
• cisco@spot.colorado.edu
  
• cisco-nsp@puck.nether.net
  
• full-disclosure@lists.grok.org.uk
  
• comp.dcom.sys.cisco@newsgate.cisco.com
  

Future updates of this advisory, if any, will be placed on Cisco's worldwide website, 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.

Complete information on reporting security vulnerabilities in Cisco products, obtaining assistance with security incidents, and registering to receive security information from Cisco, is available on Cisco's worldwide website at http://www.cisco.com/en/US/products/products_security_vulnerability_policy.html. This includes instructions for press inquiries regarding Cisco security notices. All Cisco security advisories are available at http://www.cisco.com/go/psirt.