{
  "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 implementation of the IPv4 fragmentation reassembly code in Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.\r\n\r\nThis vulnerability is due to improper management of resources during fragment reassembly. An attacker could exploit this vulnerability by sending specific sizes of fragmented packets to an affected device or through a Virtual Fragmentation Reassembly (VFR)-enabled interface on an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.\r\n\r\nNote: This vulnerability affects Cisco ASR 1000 Series Aggregation Services Routers and Cisco cBR-8 Converged Broadband Routers if they are running Cisco IOS XE Software Release 17.12.1 or 17.12.1a.\r\n\r\nCisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.\r\n\r\n\r\n\r\nThis advisory is part of the September 2024 release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2024 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication [\"https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75169\"].",
        "title": "Summary"
      },
      {
        "category": "general",
        "text": "This vulnerability affects Cisco ASR 1000 Series Aggregation Services Routers and Cisco cBR-8 Converged Broadband Routers if they are running Cisco IOS XE Software Release 17.12.1 or 17.12.1a.\r\n\r\nFor information about which Cisco software releases are vulnerable, see the Fixed Software [\"#fs\"] section of this advisory.\r\n  Determine the Device Configuration\r\nTo determine whether the VFR feature is enabled, use the show ip virtual-reassembly CLI command, as shown in the following example:\r\n\r\n\r\nRouter# show ip virtual-reassembly\r\nGigabitEthernet0/0/1:\r\n    Virtual Fragment Reassembly (VFR) is ENABLED [in]\r\n    Concurrent reassemblies (max-reassemblies): 16\r\n    Fragments per reassembly (max-fragments): 32\r\n    Reassembly timeout (timeout): 3 seconds\r\n    Drop fragments: OFF\r\n.\r\n.\r\n.\r\nTunnel1:\r\n    Virtual Fragment Reassembly (VFR) is ENABLED [in]\r\n    Concurrent reassemblies (max-reassemblies): 16\r\n    Fragments per reassembly (max-fragments): 32\r\n    Reassembly timeout (timeout): 3 seconds\r\n    Drop fragments: OFF\r\n\r\nIn the preceding example, both the physical interface GigabitEthernet0/0/1 and the tunnel interface Tunnel1 have the VFR feature enabled. This indicates that both interfaces are affected by this vulnerability.\r\n\r\nNote: VFR is automatically enabled by features such as Network Address Translation (NAT), Zone-Based Firewall, and IPSec to process Layer 4 or Layer 7 information. Disabling VFR is not recommended. The ip virtual-reassembly configuration command will not be displayed in the output of show running-config unless the VFR feature was manually enabled. For more information, see the IP Addressing: Fragmentation and Reassembly Configuration Guide [\"https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_frre/configuration/xe-17/frre-xe-17-book/virt-frag-reassembly.html#GUID-8E41C55A-D133-4C84-BF6A-F8FCC325549F\"].",
        "title": "Vulnerable Products"
      },
      {
        "category": "general",
        "text": "Only products listed in the Vulnerable Products [\"#vp\"] section of this advisory are known to be affected by this vulnerability.\r\n\r\nCisco has confirmed that this vulnerability does not affect the following Cisco products:\r\n\r\nIOS Software\r\nIOS XR Software\r\nMeraki products\r\nNX-OS Software",
        "title": "Products Confirmed Not Vulnerable"
      },
      {
        "category": "general",
        "text": "There are no workarounds that address this vulnerability.",
        "title": "Workarounds"
      },
      {
        "category": "general",
        "text": "Cisco has released free software updates [\"https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#ssu\"] 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.\r\n\r\nCustomers 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\nThe Cisco Support and Downloads page [\"https://www.cisco.com/c/en/us/support/index.html\"] 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.\r\n\r\nWhen considering software upgrades [\"https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes\"], customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories 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  Customers Without Service Contracts\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: https://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        Cisco IOS and IOS XE Software\r\nTo help customers determine their exposure to vulnerabilities in Cisco IOS and IOS XE Software, Cisco provides the Cisco Software Checker [\"https://sec.cloudapps.cisco.com/security/center/softwarechecker.x\"]. 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 (\u201cFirst Fixed\u201d). 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 (\u201cCombined First Fixed\u201d).\r\n\r\nTo use the tool, go to the Cisco Software Checker [\"https://sec.cloudapps.cisco.com/security/center/softwarechecker.x\"] page and follow the instructions. Alternatively, use the following form to determine whether a release is affected by any Cisco Security Advisory. To use the form, follow these steps:\r\n\r\nChoose which advisories the tool will search\u2014only this advisory, only advisories with a Critical or High Security Impact Rating (SIR) [\"https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#asr\"], or all advisories.\r\nEnter a release number\u2014for example, 15.9(3)M2 or 17.3.3.\r\nClick Check.\r\n\r\n       Only this advisory  All Critical and High advisories  All advisories",
        "title": "Fixed Software"
      },
      {
        "category": "general",
        "text": "To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy [\"http://www.cisco.com/web/about/security/psirt/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": "psirt@cisco.com",
      "issuing_authority": "Cisco PSIRT",
      "name": "Cisco",
      "namespace": "https://wwww.cisco.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "Cisco IOS XE Software IPv4 Fragmentation Reassembly Denial of Service Vulnerability",
        "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cpp-vfr-dos-nhHKGgO"
      },
      {
        "category": "external",
        "summary": "Cisco Event Response: September 2024 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication",
        "url": "https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75169"
      },
      {
        "category": "external",
        "summary": "Cisco Security Vulnerability Policy",
        "url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html"
      },
      {
        "category": "external",
        "summary": "IP Addressing: Fragmentation and Reassembly Configuration Guide",
        "url": "https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_frre/configuration/xe-17/frre-xe-17-book/virt-frag-reassembly.html#GUID-8E41C55A-D133-4C84-BF6A-F8FCC325549F"
      },
      {
        "category": "external",
        "summary": "free software updates",
        "url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#ssu"
      },
      {
        "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 Support and Downloads page",
        "url": "https://www.cisco.com/c/en/us/support/index.html"
      },
      {
        "category": "external",
        "summary": "considering software upgrades",
        "url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes"
      },
      {
        "category": "external",
        "summary": "Cisco Security Advisories 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": "Cisco Software Checker",
        "url": "https://sec.cloudapps.cisco.com/security/center/softwarechecker.x"
      },
      {
        "category": "external",
        "summary": "Security Impact Rating (SIR)",
        "url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#asr"
      },
      {
        "category": "external",
        "summary": "Security Vulnerability Policy",
        "url": "http://www.cisco.com/web/about/security/psirt/security_vulnerability_policy.html"
      }
    ],
    "title": "Cisco IOS XE Software IPv4 Fragmentation Reassembly Denial of Service Vulnerability",
    "tracking": {
      "current_release_date": "2024-09-25T16:00:00+00:00",
      "generator": {
        "date": "2024-09-25T15:49:57+00:00",
        "engine": {
          "name": "TVCE"
        }
      },
      "id": "cisco-sa-cpp-vfr-dos-nhHKGgO",
      "initial_release_date": "2024-09-25T16:00:00+00:00",
      "revision_history": [
        {
          "date": "2024-09-25T15:47:02+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": "17.12.1",
                    "product": {
                      "name": "17.12.1",
                      "product_id": "CSAFPID-286801"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.12.1a",
                    "product": {
                      "name": "17.12.1a",
                      "product_id": "CSAFPID-300012"
                    }
                  }
                ],
                "category": "product_version",
                "name": "17.12"
              },
              {
                "branches": [
                  {
                    "category": "service_pack",
                    "name": "17.11.99SW",
                    "product": {
                      "name": "17.11.99SW",
                      "product_id": "CSAFPID-296860"
                    }
                  }
                ],
                "category": "product_version",
                "name": "17.11SW"
              }
            ],
            "category": "product_family",
            "name": "Cisco IOS XE Software"
          }
        ],
        "category": "vendor",
        "name": "Cisco"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2024-20467",
      "ids": [
        {
          "system_name": "Cisco Bug ID",
          "text": "CSCwh44152"
        }
      ],
      "notes": [
        {
          "category": "other",
          "text": "Complete.",
          "title": "Affected Product Comprehensiveness"
        }
      ],
      "product_status": {
        "known_affected": [
          "CSAFPID-286801",
          "CSAFPID-296860",
          "CSAFPID-300012"
        ]
      },
      "release_date": "2024-09-25T16:00:00+00:00",
      "remediations": [
        {
          "category": "vendor_fix",
          "details": "Cisco has released software updates that address this vulnerability.",
          "product_ids": [
            "CSAFPID-286801",
            "CSAFPID-296860",
            "CSAFPID-300012"
          ],
          "url": "https://software.cisco.com"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "baseScore": 8.6,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H",
            "version": "3.1"
          },
          "products": [
            "CSAFPID-286801",
            "CSAFPID-296860",
            "CSAFPID-300012"
          ]
        }
      ],
      "title": "Cisco IOS XE Software Virtual Fragmentation Reassembly Denial of Service Vulnerability"
    }
  ]
}