{
  "document": {
    "acknowledgments": [
      {
        "summary": "This vulnerability was found during the resolution of a Cisco TAC support case."
      }
    ],
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "notes": [
      {
        "category": "summary",
        "text": "A vulnerability in the DHCPv6 feature of the Cisco Nexus 9000 Series Fabric Switches in Application-Centric Infrastructure (ACI) Mode could allow an unauthenticated, remote attacker to cause the device to run low on system memory, which could result in a Denial of Service (DoS) condition on an affected system.\r\n\r\nThe vulnerability is due to improper memory management when DHCPv6 packets are received on an interface of the targeted device. An attacker could exploit this vulnerability by sending a high number of malicious DHCPv6 packets to be processed by an affected device. A successful exploit could allow the attacker to cause the system to run low on memory, which could cause an eventual reboot of an affected device. The vulnerability only applies to IPv6 protocol packets and not for IPv4 protocol packets.\r\n\r\n\r\nCisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.\r\n\r\nThis advisory is available at the following link:\r\nhttps://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-20180718-nexus-9000-dos [\"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-20180718-nexus-9000-dos\"]",
        "title": "Summary"
      },
      {
        "category": "general",
        "text": "This vulnerability affects Cisco Nexus 9000 Series Fabric Switches in ACI Mode running software version 13.0(1k).\r\n\r\nThe vulnerability can only be exploited when unicast routing is enabled on the Bridge Domain (BD). DHCP and DHCP relay do not have to be configured for the vulnerability to be exploited.\r\n\r\nDetermining the NX-OS Software Release\r\n\r\nAdministrators can check the version of NX-OS Software running on their device by using the show version command from the device CLI. The following example identifies the 11.2(2) release:\r\n\r\n\r\nnxos-n9k-aci# show version\r\nCisco Nexus Operating System (NX-OS) Software  such license is available at  http://www.opensource.org/licenses/gpl-2.0.php and  http://www.opensource.org/licenses/lgpl-2.1.php  Software    BIOS:      version N/A    kickstart: version 11.2(2) [build 11.2(1.184)]    system:    version 11.2(2) [build 11.2(1.184)]\r\n    Determining the APIC Software Release\r\n\r\nThere is a one-to-one mapping between the software for Cisco Application Policy Infrastructure Controller (APIC) and Cisco Nexus 9000 Series Fabric Switches in ACI Mode. To determine what Cisco APIC release is in use, administrators can remove the leftmost 1 from the Cisco NX-OS Software version number. In the previous example, the Cisco APIC Software version is 1.2(2).\r\n  Determining Whether Unicast Routing is Enabled\r\n\r\nAdministrators can check whether unicast routing is enabled on their  device by using the following command from the device CLI:\r\n\r\n\r\nnxos-n9k-aci# moquery -d uni/tn-ag/BD-bd1 | egrep \"unicastRoute\"\r\nunicastRoute             : yes",
        "title": "Vulnerable Products"
      },
      {
        "category": "general",
        "text": "Only products listed in the Vulnerable Products [\"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-20180718-nexus-9000-dos#vp\"] section of this advisory are known to be affected by this vulnerability.\r\n\r\nCisco has determined that this vulnerability does not affect the following Cisco products:\r\n\r\nFirepower 2100 Series\r\nFirepower 4100 Series Next-Generation Firewall\r\nFirepower 9300 Security Appliance\r\nMDS 9000 Series Multilayer Director Switches\r\nNexus 1000V Series Switches\r\nNexus 1100 Series Cloud Services Platforms\r\nNexus 2000 Series Switches\r\nNexus 3000 Series Switches\r\nNexus 3500 Platform Switches\r\nNexus 3600 Platform Switches\r\nNexus 5000 Series Switches\r\nNexus 5500 Platform Switches\r\nNexus 5600 Platform Switches\r\nNexus 7000 Series Switches\r\nNexus 7700 Series Switches\r\nNexus 9000 Series Switches in NX-OS mode\r\nNexus 9500 R-Series Line Cards and Fabric Modules\r\nUCS 6100 Series Fabric Interconnects\r\nUCS 6200 Series Fabric Interconnects\r\nUCS 6300 Series Fabric Interconnects",
        "title": "Products Confirmed Not Vulnerable"
      },
      {
        "category": "general",
        "text": "Exploitation of this vulnerability could cause the affected device to reload and write a core file. Contact Cisco Technical Assistance Center (TAC) to review the core file and confirm whether it was due to this vulnerability.\r\n\r\nTo verify the current status of the virtual memory usage, administrators can enter the command ps aux | grep \u0027dhcp_snoop\\|VSZ\u0027  from the leaf node prompt. If the displayed value exceeds 3 GB, a reboot  should be performed to prevent an unplanned device restart. The following example shows a device that has not reached the 3 GB value for the Virtual Memory Size (VSZ):\r\n\r\n\r\nnxos-n9k-aci# ps aux | grep \u0027dhcp_snoop\\|VSZ\u0027\r\nUSER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND\r\nroot     13225  0.0  1.5 1712896 382940 ?      Ssl  Jun26   0:26 /isan/bin/dhcp_snoop\r\nadmin    21444  0.0  0.0   2272   524 pts/0    SN+  11:35   0:00 grep dhcp_snoop\\|VSZ",
        "title": "Indicators of Compromise"
      },
      {
        "category": "general",
        "text": "There are no workarounds that address this vulnerability.",
        "title": "Workarounds"
      },
      {
        "category": "general",
        "text": "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:\r\nhttps://www.cisco.com/c/en/us/products/end-user-license-agreement.html [\"https://www.cisco.com/c/en/us/products/end-user-license-agreement.html\"]\r\n\r\nAdditionally, 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.\r\n\r\nWhen 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 [\"https://www.cisco.com/go/psirt\"], to determine exposure and a complete upgrade solution.\r\n\r\nIn 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.\r\n\r\nCustomers Without Service Contracts\r\n\r\nCustomers 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:\r\nhttps://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html [\"https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html\"]\r\n\r\nCustomers 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.\r\n\r\nFixed Releases\r\n\r\n\r\n\r\nThis vulnerability is fixed in Cisco Nexus 9000 Series Fabric Switches in ACI Mode version 13.0(2k) and later releases.\r\n\r\nThe recommended action for all Cisco customers running a device with an  affected version is to upgrade to the latest maintenance or  latest long-lived version. Cisco suggests that customers visit the  following page to determine what fixed release to choose: https://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/recommended-release/b_Recommended_Cisco_ACI_Releases.html [\"https://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/recommended-release/b_Recommended_Cisco_ACI_Releases.html\"].",
        "title": "Fixed Software"
      },
      {
        "category": "general",
        "text": "To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy [\"https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html\"]. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.",
        "title": "Vulnerability Policy"
      },
      {
        "category": "general",
        "text": "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.",
        "title": "Exploitation and Public Announcements"
      },
      {
        "category": "general",
        "text": "This vulnerability was found during the resolution of a Cisco TAC support case.",
        "title": "Source"
      },
      {
        "category": "legal_disclaimer",
        "text": "THIS DOCUMENT IS PROVIDED ON AN \"AS IS\" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.\r\n\r\nA standalone copy or paraphrase of the text of this document that omits the distribution URL is an uncontrolled copy and may lack important information or contain factual errors. The information in this document is intended for end users of Cisco products.",
        "title": "Legal Disclaimer"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "Emergency Support:\r\n+1 877 228 7302 (toll-free within North America)\r\n+1 408 525 6532 (International direct-dial)\r\nNon-emergency Support:\r\nEmail: psirt@cisco.com\r\nSupport requests that are received via e-mail are typically acknowledged within 48 hours.",
      "issuing_authority": "Cisco product security incident response is the responsibility of the Cisco Product Security Incident Response Team (PSIRT). The Cisco PSIRT is a dedicated, global team that manages the receipt, investigation, and public reporting of security vulnerability information that is related to Cisco products and networks. The on-call Cisco PSIRT works 24x7 with Cisco customers, independent security researchers, consultants, industry organizations, and other vendors to identify possible security issues with Cisco products and networks.\r\nMore information can be found in Cisco Security Vulnerability Policy available at https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html",
      "name": "Cisco",
      "namespace": "https://wwww.cisco.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "Cisco Nexus 9000 Series Fabric Switches Application-Centric Infrastructure Mode DHCP Version 6 Denial of Service Vulnerability",
        "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-20180718-nexus-9000-dos"
      },
      {
        "category": "external",
        "summary": "Cisco Security Vulnerability Policy",
        "url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html"
      },
      {
        "category": "external",
        "summary": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-20180718-nexus-9000-dos",
        "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-20180718-nexus-9000-dos"
      },
      {
        "category": "external",
        "summary": "Vulnerable Products",
        "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-20180718-nexus-9000-dos#vp"
      },
      {
        "category": "external",
        "summary": "https://www.cisco.com/c/en/us/products/end-user-license-agreement.html",
        "url": "https://www.cisco.com/c/en/us/products/end-user-license-agreement.html"
      },
      {
        "category": "external",
        "summary": "Cisco Security Advisories and Alerts page",
        "url": "https://www.cisco.com/go/psirt"
      },
      {
        "category": "external",
        "summary": "https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html",
        "url": "https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html"
      },
      {
        "category": "external",
        "summary": "https://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/recommended-release/b_Recommended_Cisco_ACI_Releases.html",
        "url": "https://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/recommended-release/b_Recommended_Cisco_ACI_Releases.html"
      },
      {
        "category": "external",
        "summary": "Security Vulnerability Policy",
        "url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html"
      }
    ],
    "title": "Cisco Nexus 9000 Series Fabric Switches Application-Centric Infrastructure Mode DHCP Version 6 Denial of Service Vulnerability",
    "tracking": {
      "current_release_date": "2018-07-18T16:00:00+00:00",
      "generator": {
        "date": "2022-09-03T02:58:43+00:00",
        "engine": {
          "name": "TVCE"
        }
      },
      "id": "cisco-20180718-nexus-9000-dos",
      "initial_release_date": "2018-07-18T16:00:00+00:00",
      "revision_history": [
        {
          "date": "2018-07-18T14:41:36+00:00",
          "number": "1.0.0",
          "summary": "Initial public release."
        }
      ],
      "status": "final",
      "version": "1.0.0"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "branches": [
                  {
                    "category": "service_pack",
                    "name": "13.0(1k)",
                    "product": {
                      "name": "13.0(1k)",
                      "product_id": "CSAFPID-241218"
                    }
                  }
                ],
                "category": "product_version",
                "name": "13.0"
              }
            ],
            "category": "product_family",
            "name": "Cisco NX-OS System Software in ACI Mode"
          }
        ],
        "category": "vendor",
        "name": "Cisco"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2018-0372",
      "ids": [
        {
          "system_name": "Cisco Bug ID",
          "text": "CSCvg38918"
        }
      ],
      "notes": [
        {
          "category": "other",
          "text": "Complete.",
          "title": "Affected Product Comprehensiveness"
        }
      ],
      "product_status": {
        "known_affected": [
          "CSAFPID-241218"
        ]
      },
      "release_date": "2018-07-18T16:00:00+00:00",
      "remediations": [
        {
          "category": "vendor_fix",
          "details": "Cisco has released software updates that address this vulnerability.",
          "product_ids": [
            "CSAFPID-241218"
          ],
          "url": "https://software.cisco.com"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "baseScore": 8.6,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H",
            "version": "3.0"
          },
          "products": [
            "CSAFPID-241218"
          ]
        }
      ],
      "title": "Cisco Nexus 9000 Series Fabric Switches ACI Mode DHCP Version 6 Denial of Service Vulnerability"
    }
  ]
}