Summary

• The Cisco Wireless LAN Controller (WLC) manages Cisco Aironet access points using the Lightweight Access Point Protocol (LWAPP). The WLC contains multiple vulnerabilities that could result in a denial of service (DoS) condition, information disclosure, or access control list changes, or allow an attacker to gain full administrative access.

  Cisco has made free software available to address these vulnerabilities for affected customers. There are workarounds available to mitigate the effects of these vulnerabilities.

  This advisory is posted at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20070412-wlc.

Affected Products

• Vulnerable Products

  Vulnerable Software

  The vulnerabilities addressed in this document affect versions 4.0, 3.2, and prior versions of the Wireless LAN Controller software. To identify the first fixed version for a specific Cisco Bug ID, please see the Software Versions and Fixes section of this advisory.

  To determine the version of WLC running in a given environment, use one of the following methods:

  • In the web interface, choose the Monitor tab, click Summary in the left-hand pane, and note the "Software Version."
    
  • From the command-line interface, type show sysinfo and note the "Product Version."
    

  Vulnerable Hardware

  Wireless LAN Controllers

  • Cisco 4400 Series Wireless LAN Controllers
    
  • Cisco 4100 Series Wireless LAN Controllers
    
  • Cisco 2100 Series Wireless LAN Controllers
    
  • Cisco 2000 Series Wireless LAN Controllers
    
  • Cisco Wireless LAN Controller Module
    

  Wireless Integrated Switches and Routers

  • Cisco Catalyst 6500 Series Wireless Services Module (WiSM)
    
  • Cisco Catalyst 3750 Series Integrated Wireless LAN Controllers
    
  • Cisco Wireless LAN Controller Module
    

  Cisco Aironet Access Points

  • Cisco Aironet 1000 Series
    
  • Cisco Aironet 1500 Series
    

  Products Confirmed Not Vulnerable

  • Cisco Aironet 1400 Series
    
  • Cisco Aironet 1300 Series
    
  • Cisco Aironet 1240 AG Series
    
  • Cisco Aironet 1230 AG Series
    
  • Cisco Aironet 1200 Series
    
  • Cisco Aironet 1130 AG Series
    
  • Cisco Aironet 1100 Series
    

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

Details

• The Cisco Wireless LAN Controller (WLC) manages Cisco Aironet access points using the Lightweight Access Point Protocol (LWAPP). This protocol provides centralized management of wireless networks. The WLC contains the following vulnerabilities:

  Default SNMP Community Strings

  The WLC uses the commonly known values of "public" and "private" for its read-only and read-write SNMP community strings. This vulnerability is documented by Cisco Bug ID CSCse02384 ( registered customers only) .

  Malformed Ethernet Traffic Crash

  The WLC may crash in response to malformed Ethernet traffic. This vulnerability is documented by Cisco Bug ID CSCsc90179 ( registered customers only) .

  Multiple NPU Lock-Up Vulnerabilities

  The Network Processing Unit (NPU) is responsible for handling traffic within the WLC. It is possible to cause one or more NPUs to lock up by sending certain types of traffic to an affected WLC. This traffic includes crafted SNAP packets, malformed 802.11 traffic, and packets with unexpected length values in certain headers.

  Each NPU operates independently and serves two of the physical ports on the WLC. A lock up in one NPU does not affect the others, so the number of NPUs available and the configuration of the device determine whether these vulnerabilities result in a partial or complete inability to forward traffic. To clear a NPU lock up, the WLC must be restarted. If the lock up condition prevents access to the management interface, the restart must be performed via the console port or service port.

  Devices that implement the WLC functionality in software rather than hardware do not contain a NPU and are not affected by these vulnerabilities. These software-based devices are the 2000 Series WLC, the 2100 Series WLC, and the Cisco Wireless LAN Controller Module.

  These vulnerabilities are documented by Cisco Bug IDs CSCsg36361 ( registered customers only) , CSCsg15901 ( registered customers only) , and CSCsh10841 ( registered customers only) .

  Hard-Coded Service Password in Lightweight AP

  The Cisco Aironet 1000 Series and 1500 Series Lightweight Access Points contain a hard-coded service password that is used for troubleshooting. This service account is only accessible via a physical connection to the console port, but the password is common to all units in these series. This vulnerability is documented by Cisco Bug ID CSCsg15192 ( registered customers only) .

  WLAN ACL Does Not Persist Through Reboot

  Version 4.0 of the WLC contains a bug when processing WLAN ACLs that causes the WLAN ACL configuration to be saved with an invalid checksum. This bug does not affect 3.2 versions of the WLC. When the configuration is subsequently reloaded at boot time, the checksum fails and the WLAN ACLs are not installed. This vulnerability is documented by Cisco Bug ID CSCse58195 ( 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.

  CSCse02384 ( registered customers only) Calculate the environmental score of CSCse02384
  CVSS Base Score - 10
  Access Vector	Access Complexity	Authentication	Confidentiality Impact	Integrity Impact	Availability Impact	Impact Bias
  Remote	Low	Not Required	Complete	Complete	Complete	Normal
  CVSS Temporal Score - 8.3
  Exploitability		Remediation Level		Report Confidence
  Functional		Official Fix		Confirmed

  CSCsc90179 ( registered customers only) Calculate the environmental score of CSCsc90179
  CVSS Base Score - 3.3
  Access Vector	Access Complexity	Authentication	Confidentiality Impact	Integrity Impact	Availability Impact	Impact Bias
  Remote	Low	Not Required	None	None	Complete	Normal
  CVSS Temporal Score - 2.7
  Exploitability		Remediation Level		Report Confidence
  Functional		Official Fix		Confirmed

  CSCsg36361 ( registered customers only) Calculate the environmental score of CSCsg36361
  CVSS Base Score - 3.3
  Access Vector	Access Complexity	Authentication	Confidentiality Impact	Integrity Impact	Availability Impact	Impact Bias
  Remote	Low	Not Required	None	None	Complete	Normal
  CVSS Temporal Score - 2.7
  Exploitability		Remediation Level		Report Confidence
  Functional		Official Fix		Confirmed

  CSCsg15901 ( registered customers only) Calculate the environmental score of CSCsg15901
  CVSS Base Score - 3.3
  Access Vector	Access Complexity	Authentication	Confidentiality Impact	Integrity Impact	Availability Impact	Impact Bias
  Remote	Low	Not Required	None	None	Complete	Normal
  CVSS Temporal Score - 2.7
  Exploitability		Remediation Level		Report Confidence
  Functional		Official Fix		Confirmed

  CSCsh10841 ( registered customers only) Calculate the environmental score of CSCsh10841
  CVSS Base Score - 3.3
  Access Vector	Access Complexity	Authentication	Confidentiality Impact	Integrity Impact	Availability Impact	Impact Bias
  Remote	Low	Not Required	None	None	Complete	Normal
  CVSS Temporal Score - 2.7
  Exploitability		Remediation Level		Report Confidence
  Functional		Official Fix		Confirmed

  CSCsg15192 ( registered customers only) Calculate the environmental score of CSCsg15192
  CVSS Base Score - 5.6
  Access Vector	Access Complexity	Authentication	Confidentiality Impact	Integrity Impact	Availability Impact	Impact Bias
  Local	High	Not Required	Complete	Complete	Complete	Normal
  CVSS Temporal Score - 4.6
  Exploitability		Remediation Level		Report Confidence
  Functional		Official Fix		Confirmed

  CSCse58195 ( registered customers only) Calculate the environmental score of CSCse58195
  CVSS Base Score - 3.7
  Access Vector	Access Complexity	Authentication	Confidentiality Impact	Integrity Impact	Availability Impact	Impact Bias
  Remote	High	Not Required	Partial	Partial	None	Normal
  CVSS Temporal Score - 3.1
  Exploitability		Remediation Level		Report Confidence
  Functional		Official Fix		Confirmed

Workarounds

• This section describes workarounds for these vulnerabilities.

  Default SNMP Community Strings

  Customers can mitigate this vulnerability by changing the SNMP community strings from their default values. This can be accomplished on each WLC by using the menu to access Management > SNMP > Communities and then changing the values of the community strings. On larger networks, the Cisco Wireless Control System can be used to apply SNMP changes across multiple controllers simultaneously.

  Malformed Ethernet Traffic Crash

  There are no known workarounds for this vulnerability.

  Multiple NPU Lock-Up Vulnerabilities

  There are no known workarounds for these vulnerabilities.

  Hard-Coded Service Password in Lightweight AP

  There are no known workarounds for this vulnerability.

  WLAN ACL Does Not Persist Through Reboot

  There are no known workarounds for this vulnerability.

  Additional Workarounds

  Additional mitigations that can be deployed on Cisco devices within the network are available in the Cisco Applied Mitigation Bulletin companion document for this advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoAppliedMitigationBulletin/cisco-amb-20070412-wlc

Fixed Software

• 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.

  Each row of the software table (below) describes the earliest software version that contains the fix (the "First Fixed Release") and the anticipated date of availability when fixes are not available. A device running a version that is earlier than the First Fixed Release is known to be vulnerable. The release should be upgraded at least to the indicated version (greater than or equal to the First Fixed Release label).

  Cisco Bug ID	First Fixed Releases
  CSCse02384	4.1.171.0
  CSCsc90179	3.2.116.21, 4.0.155.0
  CSCsg36361	3.2.193.5, 4.0.206.0, 4.1.171.0
  CSCsg15901	3.2.171.5, 4.0.206.0, 4.1.171.0
  CSCsh10841	3.2.171.5, 4.0.206.0, 4.1.171.0
  CSCsg15192	3.2.185.0, 4.0.206.0
  CSCse58195	4.0.206.0

Exploitation and Public Announcements

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

  These vulnerabilities were discovered via internal testing and during the investigation of customer support cases.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20070412-wlc

Revision History

• Revision 1.4	2008-April-24	Updated links to the CVSS scoring for each bug ID.
  Revision 1.3	2007-May-16	Updated First Fixed Releases information to include the recent 4.1 software release.
  Revision 1.2	2007-April-16	Added additional products to the Wireless LAN Controller affected products and added information to the WLAN ACL Does Not Persist Through Reboot section.
  Revision 1.1	2007-April-14	Minor grammatical changes.
  Revision 1.0	2007-April-12	Initial public release.

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