A vulnerability in the resource handling system of Cisco NX-OS Software for Cisco MDS 9000 Series Multilayer Switches could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper resource usage control. An attacker could exploit this vulnerability by sending traffic to the management interface (mgmt0) of an affected device at very high rates. An exploit could allow the attacker to cause unexpected behaviors such as high CPU usage, process crashes, or even full system reboots of an affected device. 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-20200226-mds-ovrld-dos This advisory is part of the February 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication, which includes six Cisco Security Advisories that describe six vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: February 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.
A vulnerability in the resource handling system of Cisco NX-OS Software for Cisco MDS 9000 Series Multilayer Switches could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.
The vulnerability is due to improper resource usage control. An attacker could exploit this vulnerability by sending traffic to the management interface (mgmt0) of an affected device at very high rates. An exploit could allow the attacker to cause unexpected behaviors such as high CPU usage, process crashes, or even full system reboots of an affected device.
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-20200226-mds-ovrld-dos
This advisory is part of the February 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication, which includes six Cisco Security Advisories that describe six vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: February 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.
This vulnerability affects the following Cisco products if they are running a vulnerable release of Cisco NX-OS Software:
For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory.
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:
Cisco has released free software updates that address the vulnerability described in this advisory. 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.
When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories and Alerts 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 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.
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:
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.
For help determining the best Cisco NX-OS Software release for a Cisco Nexus Switch, administrators can refer to the following Recommended Releases documents. If a security advisory recommends a later release, Cisco recommends following the advisory guidance.
To determine the best release for Cisco UCS, see the Recommended Releases documents in the release notes for the device.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
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.
This vulnerability was found during internal security testing.
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.
| Version | Description | Section | Status | Date |
|---|---|---|---|---|
| 1.2 | Added MDS 9148 Multilayer Fabric Switches to the Products Confirmed Not Vulnerable list. | Affected Products | Final | 2020-MAY-21 |
| 1.1 | Updated with specific models of MDS 9000 Series Multilayer Switches. | Affected Products | Final | 2020-MAY-15 |
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