CVE-2022-20623: Cisco Security Advisory: Cisco Nexus 9000 Series Switches Bidirectional Forwarding Detection Denial of Service Vulnerability

• 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 NX-OS Software

  To help customers determine their exposure to vulnerabilities in Cisco NX-OS Software, Cisco provides the Cisco Software Checker to identify any Cisco Security Advisories that impact a specific Cisco NX-OS Software release and the earliest release that fixes the vulnerabilities that are 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, platform, 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 or one or more specific advisories.

  Customers can also use the following form to determine whether a release is affected by any Cisco Security Advisory by choosing the Cisco NX-OS Software and platform and then entering a release-for example, 7.0(3)I7(5) for Cisco Nexus 3000 Series Switches or 14.0(1h) for Cisco NX-OS Software in ACI mode:

  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 and check the Medium check box in the drop-down list under Impact Rating when customizing a search.

  Cisco Nexus 9000 Series Switches SMUs

  Cisco has released the following SMUs to address this vulnerability. Customers can download the SMUs from the Software Center on Cisco.com.

Cisco NX-OS Software Release

Platform

SMU Name

7.0(3)I7(10)

Nexus 9000 Series Switches

nxos.CSCvx75912-n9k\_ALL-1.0.0-7.0.3.I7.10.lib32\_n9000.rpm

9.3(8)

Nexus 9000 Series Switches

nxos.CSCvx75912-n9k\_ALL-1.0.0-9.3.8.lib32\_n9000.rpm

For details about downloading and installing SMUs in Cisco NX-OS Software for Cisco Nexus 9000 Series Switches, see the Performing Software Maintenance Upgrades section of the Cisco NX-OS system management configuration guide Cisco Nexus 9000 Series Switches.

**Additional Resources**

For help determining the best Cisco NX-OS Software release for a Cisco Nexus Switch, see the following Recommended Releases documents. If a security advisory recommends a later release, Cisco recommends following the advisory guidance.

> Cisco MDS Series Switches  
> Cisco Nexus 1000V for VMware Switch  
> Cisco Nexus 3000 Series Switches  
> Cisco Nexus 5500 Platform Switches  
> Cisco Nexus 5600 Platform Switches  
> Cisco Nexus 6000 Series Switches  
> Cisco Nexus 7000 Series Switches  
> Cisco Nexus 9000 Series Switches  
> Cisco Nexus 9000 Series ACI-Mode Switches

To determine the best release for Cisco UCS Software, see the Recommended Releases documents in the release notes for the device.