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Cisco Security Advisory

Cisco Network Admission Control Shared Secret Vulnerability

Advisory ID: cisco-sa-20080416-nac

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20080416-nac

Revision 1.1

For Public Release 2008 April 16 16:00  UTC (GMT)


Summary

A vulnerability exists in the Cisco Network Admission Control (NAC) Appliance that can allow an attacker to obtain the shared secret that is used between the Cisco Clean Access Server (CAS) and the Cisco Clean Access Manager (CAM).

Cisco has released free software updates that address this vulnerability.

This advisory is posted at http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20080416-nac.

Affected Products

Vulnerable Products

The following table lists all Cisco NAC Appliance software versions affected by this vulnerability.

NAC Software Release

Vulnerable Versions

3.5.x

All 3.5.x versions

3.6.x

All 3.6.x versions prior to 3.6.4.4

4.0.x

All 4.0.x versions prior to 4.0.6

4.1.x

All 4.1.x versions prior to 4.1.2

Products Confirmed Not Vulnerable

Cisco NAC Appliance software versions 3.6.4.4 and later in the 3.6.x train; 4.0.6 and later in the 4.0.x train; and 4.1.2 and later in the 4.1.x train are not vulnerable. No other Cisco products are currently known to be affected by this vulnerability.

Details

The Cisco NAC Appliance solution allows network administrators to authenticate, authorize, evaluate, and remediate wired, wireless, and remote users and their machines prior to allowing users onto the network. The solution identifies whether machines are compliant with security policies and repairs vulnerabilities before permitting access to the network.

A vulnerability exists in the Cisco NAC Appliance that can allow an attacker to obtain the shared secret used by the CAS and the CAM from error logs that are transmitted over the network. Obtaining this information could enable an attacker to gain complete control of the CAS remotely over the network.

This vulnerability is documented in Cisco Bug ID CSCsj33976 ( registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) identifier CVE-2008-1155.

Vulnerability Scoring Details

Cisco has provided scores for the vulnerability 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.

CSCsj33976 - NAC Appliance Shared Secret Vulnerability

Calculate the environmental score of CSCsj33976

CVSS Base Score - 10.0

Access Vector

Access Complexity

Authentication

Confidentiality Impact

Integrity Impact

Availability Impact

Network

Low

None

Complete

Complete

Complete

CVSS Temporal Score - 8.3

Exploitability

Remediation Level

Report Confidence

Functional

Official-Fix

Confirmed

Impact

Successful exploitation of the vulnerability could allow an attacker to take complete control of the CAS remotely over the network.

Software Versions and Fixes

Each row of the following software table (below) describes the earliest possible releases that contain the fix for this vulnerability. These are shown in the "First Fixed Release" column. A device running a release in the given train that is earlier than the release in a specific column (less than the First Fixed Release) is known to be vulnerable. The release should be upgraded at least to the indicated release or a later version (greater than or equal to the First Fixed Release label).

Affected Releases

First Fixed Releases

NAC Appliance software version 3.5.x

Vulnerable - Contact TAC

NAC Appliance software version 3.6.x

3.6.4.4

NAC Appliance software version 4.0.x

4.0.6

NAC Appliance software version 4.1.x

4.1.2

You can download NAC Appliance software from http://www.cisco.com/tacpage/sw-center/ciscosecure/cleanaccess.shtml. 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.


Workarounds

There are no workarounds for this vulnerability.

Obtaining Fixed Software

Cisco has released free software updates that address this vulnerability. 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/en/US/docs/general/warranty/English/EU1KEN_.html, or as otherwise set forth at Cisco.com Downloads at http://www.cisco.com/public/sw-center/sw-usingswc.shtml.

Do not contact 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 agreements 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 do not hold a Cisco service contract, and customers who purchase through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should acquire 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

Customers should have their product serial number available and be prepared to give the URL of this notice as evidence of 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 localized telephone numbers, and instructions and e-mail addresses for use in various languages.

Exploitation and Public Announcements

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

This issue was discovered by Cisco through internal testing.

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 advisory is posted on Cisco's worldwide website at :

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20080416-nac

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.


Revision History

Revision 1.1

2008-April-25

Updated CVSS link for CSCsj33976.

Revision 1.0

2008-April-16

Initial public release.

Cisco Security Procedures

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/web/about/security/psirt/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.


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