{
  "document": {
    "acknowledgments": [
      {
        "summary": "This vulnerability was found during internal security testing."
      }
    ],
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "notes": [
      {
        "category": "summary",
        "text": "A vulnerability in the fragmentation handling code of tunnel protocol packets in Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected system to reload, resulting in a denial of service (DoS) condition.\r\n\r\nThis vulnerability is due to the improper handling of large fragmented tunnel protocol packets. One example of a tunnel protocol is Generic Routing Encapsulation (GRE). An attacker could exploit this vulnerability by sending crafted fragmented packets to an affected system. A successful exploit could allow the attacker to cause the affected system to reload, resulting in a DoS condition.\r\n\r\nNote: Only traffic directed to the affected system can be used to exploit this vulnerability.\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 March 2023 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: March 2023 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication [\"https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74842\"].",
        "title": "Summary"
      },
      {
        "category": "general",
        "text": "This vulnerability affects Cisco products if they are running Cisco IOS XE Software releases 17.9.1, 17.9.1a, or 17.9.1w and have a tunnel interface configured.\r\n\r\nFor more 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 a device is running Cisco IOS XE Software with a tunnel interface configured, run show ip interface brief | count Tun as shown in the following example:\r\n\r\n    Route# show ip interface brief | count Tun\r\nNumber of lines which match regexp = 1\r\n\r\nIf the regexp = 0, there are no tunnel interfaces configured, and the device is not affected by this vulnerability.",
        "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\nCustomers 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\nCisco 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 internal security testing.",
        "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 Fragmented Tunnel Protocol Packet Denial of Service Vulnerability",
        "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ios-gre-crash-p6nE5Sq5"
      },
      {
        "category": "external",
        "summary": "Cisco Event Response: March 2023 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication",
        "url": "https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74842"
      },
      {
        "category": "external",
        "summary": "Cisco Security Vulnerability Policy",
        "url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html"
      },
      {
        "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 Fragmented Tunnel Protocol Packet Denial of Service Vulnerability",
    "tracking": {
      "current_release_date": "2023-03-22T16:00:00+00:00",
      "generator": {
        "date": "2024-05-10T23:22:35+00:00",
        "engine": {
          "name": "TVCE"
        }
      },
      "id": "cisco-sa-ios-gre-crash-p6nE5Sq5",
      "initial_release_date": "2023-03-22T16:00:00+00:00",
      "revision_history": [
        {
          "date": "2023-03-22T15:49:31+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": "17.9.1",
                    "product": {
                      "name": "17.9.1",
                      "product_id": "CSAFPID-278025"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.9.1w",
                    "product": {
                      "name": "17.9.1w",
                      "product_id": "CSAFPID-286802"
                    }
                  },
                  {
                    "category": "service_pack",
                    "name": "17.9.1a",
                    "product": {
                      "name": "17.9.1a",
                      "product_id": "CSAFPID-288247"
                    }
                  }
                ],
                "category": "product_version",
                "name": "17.9"
              }
            ],
            "category": "product_family",
            "name": "Cisco IOS XE Software"
          }
        ],
        "category": "vendor",
        "name": "Cisco"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2023-20072",
      "ids": [
        {
          "system_name": "Cisco Bug ID",
          "text": "CSCwc32921"
        }
      ],
      "notes": [
        {
          "category": "other",
          "text": "Complete.",
          "title": "Affected Product Comprehensiveness"
        }
      ],
      "product_status": {
        "known_affected": [
          "CSAFPID-278025",
          "CSAFPID-286802",
          "CSAFPID-288247"
        ]
      },
      "release_date": "2023-03-22T16:00:00+00:00",
      "remediations": [
        {
          "category": "vendor_fix",
          "details": "Cisco has released software updates that address this vulnerability.",
          "product_ids": [
            "CSAFPID-278025",
            "CSAFPID-286802",
            "CSAFPID-288247"
          ],
          "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-278025",
            "CSAFPID-286802",
            "CSAFPID-288247"
          ]
        }
      ],
      "title": "Cisco IOS-XE Large Fragmented GRE Packet Denial of Service Vulnerability"
    }
  ]
}