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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2022.1612 Cisco IOS XE Wireless Controller Software for the Catalyst 9000 Family CAPWAP Denial of Service Vulnerability 14 April 2022 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Cisco IOS XE Wireless Controller Software Publisher: Cisco Systems Operating System: Cisco Resolution: Patch/Upgrade CVE Names: CVE-2022-20682 Original Bulletin: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-c9800-capwap-mdns-6PSn7gKU Comment: CVSS (Max): 8.6 CVE-2022-20682 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H) CVSS Source: Cisco Systems Calculator: https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H - --------------------------BEGIN INCLUDED TEXT-------------------- Cisco IOS XE Wireless Controller Software for the Catalyst 9000 Family CAPWAP Denial of Service Vulnerability Priority: High Advisory ID: cisco-sa-c9800-capwap-mdns-6PSn7gKU First Published: 2022 April 13 16:00 GMT Version 1.0: Final Workarounds: No workarounds available Cisco Bug IDs: CSCvy07717 CVE Names: CVE-2022-20682 CWEs: CWE-690 Summary o A vulnerability in the Control and Provisioning of Wireless Access Points (CAPWAP) protocol processing of Cisco IOS XE Wireless Controller Software for the Catalyst 9000 Family could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to inadequate input validation of incoming CAPWAP packets encapsulating multicast DNS (mDNS) queries. An attacker could exploit this vulnerability by connecting to a wireless network and sending a crafted mDNS query, which would flow through and be processed by the wireless controller. A successful exploit could allow the attacker to cause the affected device to crash and reload, resulting in a DoS condition. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-c9800-capwap-mdns-6PSn7gKU This advisory is part of the April 2022 release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: April 2022 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication. Affected Products o Vulnerable Products This vulnerability affects the following Cisco devices if they are running a vulnerable release of Cisco IOS XE Wireless Controller Software for the Catalyst 9000 Family and have the mDNS gateway feature enabled (disabled by default): Catalyst 9800 Embedded Wireless Controllers for Catalyst 9300, 9400, and 9500 Series Switches Catalyst 9800 Series Wireless Controllers Catalyst 9800-CL Wireless Controllers for Cloud Embedded Wireless Controllers on Catalyst Access Points For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory. Determine the Device Configuration To determine whether the mDNS gateway feature is enabled on a device, log in to the device CLI and issue the command show mdns-sd summary . If the mDNS gateway feature is enabled, then issue the command show run | section wlan to verify whether any WLANs are configured to use the mDNS gateway. If both conditions are true, the device is vulnerable. The following example shows the output of the commands listed above for a device that has the mDNS gateway feature globally enabled and active on a WLAN: WLC#show mdns-sd summary mDNS Gateway: Enabled Mode: Default Active Query Periodicity (in minutes): 30 Transport Type: IPv4 mDNS AP service policy: default-mdns-service-policy WLC#show run | section wlan aaa attribute list wlan_lobby_access wlan ssidname policy default-policy-profile wlan ssidname 1 ssidname mdns-sd-interface gateway no shutdown 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: IOS Software IOS XR Software Meraki products NX-OS Software Wireless LAN Controller (WLC) AireOS Software Workarounds o There are no workarounds that address this vulnerability. Fixed Software o 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. Cisco IOS and IOS XE Software To help customers determine their exposure to vulnerabilities in Cisco IOS and IOS XE Software, Cisco provides the Cisco Software Checker to identify any Cisco Security Advisories that impact a specific software release and the earliest release that fixes the vulnerabilities described in each advisory ("First Fixed"). If applicable, the tool also returns the earliest release that fixes all the vulnerabilities described in all the advisories identified ("Combined First Fixed"). Customers can use the Cisco Software Checker to search advisories in the following ways: Choose the software and one or more releases Upload a .txt file that includes a list of specific releases Enter the output of the show version command After initiating a search, customers can customize the search to include all Cisco Security Advisories, a specific advisory, or all advisories in the most recent bundled publication. By default, the Cisco Software Checker includes results only for vulnerabilities that have a Critical or High Security Impact Rating (SIR). To include results for Medium SIR vulnerabilities, customers can use the Cisco Software Checker on Cisco.com and check the Medium check box in the drop-down list under Impact Rating when customizing a search. Exploitation and Public Announcements o The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory. Source o This vulnerability was found during the resolution of a Cisco TAC support case. Cisco Security Vulnerability Policy o To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy . This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco. Related to This Advisory o Cisco Event Response: April 2022 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication URL o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-c9800-capwap-mdns-6PSn7gKU Revision History o +----------+---------------------------+----------+--------+--------------+ | Version | Description | Section | Status | Date | +----------+---------------------------+----------+--------+--------------+ | 1.0 | Initial public release. | - | Final | 2022-APR-13 | +----------+---------------------------+----------+--------+--------------+ - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. 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If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: https://www.auscert.org.au/bulletins/ =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). 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