Vulnerability Patched in NX-OS Software

Summary

A vulnerability has been discovered and patched in the External Border Gateway Protocol (eBGP) implementation of Cisco NX-OS Software. The vulnerability is categorized as CVE-2024-20321 (CVSS 3.1: 8.6) and can allow for an unauthenticated remote attacker to cause a denial of service (DoS) on the affected device. Exploitation can allow for an attacker to cause eBGP neighbor sessions to be dropped, leading to a DoS condition.

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Impact Assessment

This vulnerability has a network attack vector, low attack complexity, and requires no privileges or user interaction. However, as it only provides a denial-of-service condition, there is no chance data can be leaked or privileges escalated as a result of exploitation.

Affected Products:

Cisco Nexus 3600 Series Switches and Cisco Nexus 9500 R-Series Line Cards.

·       N3K-C36180YC-R

·       N3K-C3636C-R

·       N9K-X9624D-R2

·       N9K-X9636C-R

·       N9K-X9636C-RX

·       N9K-X9636Q-R

·       N9K-X96136YC-R

They are only affected if BGP functionality is enabled and is configured with at least one BGL neighbor with a different Autonomous System value.

There are more details on how to determine whether BGP is enabled in Cisco’s advisory.

Utilizing the Cisco Software Checker you can update the software required to remediate, follow the instructions provided on that page.

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What it means for you

If you utilize this software or any of the affected products in your environment consult the advisory and apply updates where applicable. This may have to be coordinated with an engineering team, as the upgrade is to a network device.

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Business Implications

As a result of exploitation, a denial-of-service condition can be applied. This can cause business disruption depending on what the affected devices are used for. The costs associated will be business loss based on what service is being denied access to and costs associated with possible emergency meetings to find a solution which works with your unique IT environment.

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Access Point Technology Recommends

Patch: Patching the vulnerable device will remediate the vulnerability and prevent exploitation.

Prepare: Refer to documentation regarding denial of service attacks and prepare for the possibility of exploitation.

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Associated Bulletins

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-ebgp-dos-L3QCwVJ

https://nvd.nist.gov/vuln/detail/CVE-2024-20321

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