Summary

• A vulnerability in the authentication functionality of Cisco Wireless LAN Controller (WLC) Software could allow an unauthenticated, remote attacker to bypass authentication controls and log in to the device through the management interface

  This vulnerability is due to the improper implementation of the password validation algorithm. An attacker could exploit this vulnerability by logging in to an affected device with crafted credentials. A successful exploit could allow the attacker to bypass authentication and log in to the device as an administrator. The attacker could obtain privileges that are the same level as an administrative user but it depends on the crafted credentials.

  Note: This vulnerability exists because of a non-default device configuration that must be present for it to be exploitable. For details about the vulnerable configuration, see the Vulnerable Products section of this advisory.

  Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability.

  This advisory is available at the following link:
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-wlc-auth-bypass-JRNhV4fF

Affected Products

• Vulnerable Products

  This vulnerability affects the following Cisco products if they are running Cisco WLC Software Release 8.10.151.0 or Release 8.10.162.0 and have macfilter radius compatibility configured as Other:

  • 3504 Wireless Controller
  • 5520 Wireless Controller
  • 8540 Wireless Controller
  • Mobility Express
  • Virtual Wireless Controller (vWLC)

  Note: The vulnerable releases noted above are available in the Software Center on Cisco.com. In addition, specific customers have been given the following vulnerable escalation builds that are not in the Software Center:

  • 8.10.151.4 to 8.10.151.10
  • 8.10.162.1 to 8.10.162.14

  Determine the Configuration

  To determine whether the Cisco WLC configuration is vulnerable, issue the show macfilter summary CLI command. If RADIUS compatibility mode is other, as shown in the following example, the device is considered vulnerable:

  wlc > show macfilter summary 
  
  MAC Filter RADIUS Compatibility mode............. Other
  MAC Filter Delimiter............................. Single-Hyphen
  MAC Filter Entries............................... 0
  
  

  Products Confirmed Not Vulnerable

  Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.

  Cisco has confirmed that this vulnerability does not affect the following Cisco products:

  • Catalyst 9800 Embedded Wireless Controller for Catalyst 9300, 9400, and 9500 Series Switches
  • Catalyst 9800 Series Wireless Controllers
  • Catalyst 9800 Wireless Controller for Cloud
  • Embedded Wireless Controller on Catalyst Access Points
  • Wireless LAN Controller (WLC) AireOS products not listed in the Vulnerable Products section

Workarounds

• There are workarounds that addresses this vulnerability. Choose one of the following based on the environment:

  Option 1: No Macfilters in the Environment

  Customers who do not use macfilters can reset the macfilter radius compatibility mode to the default value using the following CLI command:

  wlc > config macfilter radius-compat cisco

  Option 2: Macfilters in the Environment

  Customers who use macfilters and who are able to change the radius server configuration to match other possible compatibility modes can modify the macfilter compatibility to either cisco or free using one of the following CLI commands:

  wlc > config macfilter radius-compat cisco
  wlc > config macfilter radius-compat free

  For more information about the different macfilter compatibility modes, see Cisco Wireless Controller Command Reference.

  While these workarounds have been deployed and were proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

Fixed Software

• Cisco has released free software updates that address the vulnerability described in this advisory. Customers with service contracts that entitle them to regular software updates should obtain security fixes through their usual update channels.

  Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license:
  https://www.cisco.com/c/en/us/products/end-user-license-agreement.html

  Additionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.

  The Cisco Support and Downloads page on Cisco.com provides information about licensing and downloads. This page can also display customer device support coverage for customers who use the My Devices tool.

  When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories page, to determine exposure and a complete upgrade solution.

  In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.

  Customers Without Service Contracts

  Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html

  Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.

  Fixed Releases

  In the following table(s), the left column lists Cisco software releases. The right column indicates whether a release is affected by the vulnerability described in this advisory and the first release that includes the fix for this vulnerability. Customers are advised to upgrade to an appropriate fixed software release as indicated in this section.

  Cisco Wireless LAN Controller Release	First Fixed Release
  8.9 and earlier	Not vulnerable
  8.10.142.0 and earlier	Not vulnerable
  8.10.151.0 and later	8.10.171.0

  To download the software from the Software Center on Cisco.com, do the following:

  1. Click Browse all.
  2. Choose Wireless > Wireless LAN Controller > Standalone Controllers.
  3. Choose a specific product from the right pane of the product selector.
  4. Choose a hardware platform from the left pane of the software page.

  The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.

Exploitation and Public Announcements

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

Source

• Cisco would like to thank a security researcher with Bispok for reporting this vulnerability. 

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-wlc-auth-bypass-JRNhV4fF

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	—	Final	2022-APR-13

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