Summary

• A vulnerability in the Simple Network Management Protocol (SNMP) service of Cisco FXOS Software for Firepower 4100 Series and Firepower 9300 Security Appliances and of Cisco UCS 6300 Series Fabric Interconnects could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.

  This vulnerability is due to the improper handling of specific SNMP requests. An attacker could exploit this vulnerability by sending a crafted SNMP request to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

  Note: This vulnerability affects all supported SNMP versions. To exploit this vulnerability through SNMPv2c or earlier, an attacker must know the SNMP community string that is configured on an affected device. To exploit this vulnerability through SNMPv3, the attacker must have valid credentials for an SNMP user who is configured on the 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://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fp-ucsfi-snmp-dos-qtv69NAO

  This advisory is part of the August 2023 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: August 2023 Semiannual Cisco FXOS and NX-OS Software Security Advisory Bundled Publication.

Affected Products

• Vulnerable Products

  This vulnerability affects the following Cisco products if they are running a vulnerable release of Cisco FXOS Software or Cisco UCS Software and have the SNMP service enabled:

  • Firepower 4100 Series (CSCvi80806)
  • Firepower 9300 Security Appliances (CSCvi80806)
  • UCS 6300 Series Fabric Interconnects (CSCwd38796, CSCwe12029)
    

  The SNMP service is disabled by default.

  Note: Cisco FXOS Software releases 2.4.1 and later are not affected by this vulnerability.

  For more information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory.

  Determine the Status of SNMP

  To determine whether SNMP is enabled on a device, enter monitoring mode at the device CLI by using the scope monitoring command. Then, use the show snmp | include Admin command. If the Admin State is set to Enabled, then SNMP is enabled, as shown in the following example:

  FI-A# scope monitoring
  FI-A /monitoring # show snmp | include Admin
      Admin State: 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:

  • Firepower 1000 Series
  • Firepower 2100 Series
  • MDS 9000 Series Multilayer Switches
  • Nexus 1000 Virtual Edge for VMware vSphere
  • Nexus 1000V Switch for Microsoft Hyper-V
  • Nexus 1000V Switch for VMware vSphere
  • Nexus 3000 Series Switches
  • Nexus 5500 Platform Switches
  • Nexus 5600 Platform Switches
  • Nexus 6000 Series Switches
  • Nexus 7000 Series Switches
  • Nexus 9000 Series Fabric Switches in ACI mode
  • Nexus 9000 Series Switches in standalone NX-OS mode
  • Secure Firewall 3100 Series
  • UCS 6200 Series Fabric Interconnects
  • UCS 6400 Series Fabric Interconnects
  • UCS 6500 Series Fabric Interconnects

Workarounds

• There are no workarounds that address this vulnerability.

Fixed Software

• 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 FXOS Software

  To help customers determine their exposure to vulnerabilities in Cisco FXOS Software, Cisco provides the Cisco Software Checker. This tool identifies any Cisco security advisories that impact a specific 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 that are described in all the advisories that the Software Checker identifies (“Combined First Fixed”).

  To use the tool, go to the Cisco Software Checker page and follow the instructions. Alternatively, use the following form to search for vulnerabilities that affect a specific software release. To use the form, follow these steps:

  1. Choose which advisories the tool will search—only this advisory, only advisories with a Critical or High Security Impact Rating (SIR), or all advisories.
  2. Choose the appropriate platform.
  3. Enter a release number—for example, 2.9.1.158 for Cisco Firepower 4100 Series Security Appliances.
  4. Click Check.

   

  Only this advisory All Critical and High advisories All advisories Any Platform Firepower 4100 Series Firepower 9000 Series

   

   

  Cisco UCS Software

  In the following table, the left column lists Cisco software releases. The center column indicates whether a release is affected by the vulnerability described in this advisory and the first release that includes the fix for this vulnerability. The right column indicates whether a release is affected by all of the High and Critical vulnerabilities described in this bundle and which release includes fixes for those vulnerabilities.

  UCS 6300 Series Fabric Interconnects

  Cisco UCS Software Release	First Fixed Release for This Vulnerability	First Fixed Release for All Vulnerabilities Described in the Bundle of Advisories
  Earlier than 4.1	Migrate to a fixed release.	Migrate to a fixed release.
  4.1	4.1(3l)	4.1(3l)
  4.2	4.2(3b), 4.2(3d)1	4.2(3b), 4.2(3d)1
  4.3	Not vulnerable.	Not vulnerable.

  1. 4.2(3d) is the first fixed release for Cisco UCS 6324 Fabric Interconnects. 4.2(3b) is the first fixed release for all other UCS 6300 Series Fabric Interconnect models.

  The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.

  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.

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-fp-ucsfi-snmp-dos-qtv69NAO

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	—	Final	2023-AUG-23

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