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 software updates that address this vulnerability.

  This advisory is posted at https://sec.cloudapps.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.

Workarounds

• There are no workarounds for this vulnerability.

Fixed Software

• 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.

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.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20080416-nac

Revision History

• Revision 1.1	2008-April-25	Updated CVSS link for CSCsj33976.
  Revision 1.0	2008-April-16	Initial public release.

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