Summary

• A vulnerability in the memory buffer of Cisco Wireless LAN Controller (WLC) AireOS Software could allow an unauthenticated, adjacent attacker to cause memory leaks that could eventually lead to a device reboot.

  This vulnerability is due to memory leaks caused by multiple clients connecting under specific conditions. An attacker could exploit this vulnerability by causing multiple wireless clients to attempt to connect to an access point (AP) on an affected device. A successful exploit could allow the attacker to cause the affected device to reboot after a significant amount of time, resulting in a denial of service (DoS) condition.

  Cisco has released software updates that address this vulnerability. There is a workaround that addresses this vulnerability.

  This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cbw-dos-YSmbUqX3

Affected Products

• Vulnerable Products

  At the time of publication, this vulnerability affected the following Cisco devices if they were running a vulnerable release of Cisco WLC AireOS Software and they had the Random MAC Filtering feature enabled:

  • Mobility Express
  • Virtual Wireless LAN Controller (vWLC)

  For information about which Cisco software releases were vulnerable at the time of publication, see the Fixed Software section of this advisory. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.

  Determine Whether Random MAC Filtering is Enabled

  To determine whether Random MAC Filtering is enabled on an affected device, log in to the device and use the show wlan id command.
  
  The following example shows the output of the show wlan id command for a Cisco 3500 Series Wireless Controller on which Random MAC Filtering is enabled on wlan 1:

  (3500-3-AX) >show wlan 1
  
  
  WLAN Identifier.................................. 1
  Profile Name..................................... wpa2-dot1x
  Network Name (SSID).............................. wpa2-dot1x
  Status........................................... Enabled
  MAC Filtering.................................... Disabled
  Broadcast SSID................................... Enabled
  Random MAC Filtering............................. Enabled

   

  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:

  • 2504 Wireless Controllers
  • 3504 Wireless Controllers
  • 5508 Wireless Controllers
  • 5520 Wireless Controllers
  • 8510 Wireless Controllers
  • 8540 Wireless Controllers
  • Flex 7510 Wireless Controllers
  • IOS Software
  • IOS XE Software
  • IOS XR Software
  • Meraki products
  • NX-OS Software

Workarounds

• There is a workaround that addresses this vulnerability. Administrators can disable the Random Mac Filtering feature on the affected device using the following CLI command:

  3500-3-AX (config-wlan)# no local-admin-mac deny

  While this workaround has been deployed and was 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

• 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.

  Fixed Releases

  At the time of publication, the release information in the following table was accurate. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.

  The left column lists Cisco software releases, and the right column indicates whether a release was affected by the vulnerability described in this advisory and which release included the fix for this vulnerability.

  Cisco WLC AireOS Software Release	First Fixed Release
  8.9 and earlier	Not vulnerable
  8.10.101 to 8.10.142.0	Not vulnerable
  8.10.150 to 8.10.185	8.10.190.0

  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

• This vulnerability was found during the resolution of a Cisco TAC support case.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cbw-dos-YSmbUqX3

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	—	Final	2023-SEP-27

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