{
  "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 PPP over Ethernet (PPPoE) termination feature of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers could allow an unauthenticated, adjacent attacker to crash the ppp_ma process, resulting in a denial of service (DoS) condition.\r\n\r\nThis vulnerability is due to the improper handling of malformed PPPoE packets that are received on a router that is running Broadband Network Gateway (BNG) functionality with PPPoE termination on a Lightspeed-based or Lightspeed-Plus-based line card. An attacker could exploit this vulnerability by sending a crafted PPPoE packet to an affected line card interface that does not terminate PPPoE. A successful exploit could allow the attacker to crash the ppp_ma process, resulting in a DoS condition for PPPoE traffic across the router.\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 2024 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: March 2024 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication [\"https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75299\"].",
        "title": "Summary"
      },
      {
        "category": "general",
        "text": "This vulnerability affects Cisco ASR 9000 Series Aggregation Services Routers that are running a vulnerable release of Cisco IOS XR Software and have all of the following characteristics:\r\n\r\nA Lightspeed-based or Lightspeed-Plus-based line card installed\r\nBNG with PPPoE termination enabled\r\nAt least one interface or sub-interface with PPPoE enabled on an affected line card\r\nAt least one interface or sub-interface with PPPoE not enabled on an affected line card\r\n\r\nFor information about which Cisco software releases are vulnerable, see the Fixed Software [\"#fs\"] section of this advisory.\r\n\r\nDetermine the Installed Line Cards\r\n\r\nTo determine which line cards are installed in the device, use the show platform CLI command.\r\n\r\nThe following example shows the output for a device with two Lightspeed A99-32X100GE-X-SE line cards and a Lightspeed-Plus A99-4HG-FLEX-TR line card installed:\r\n\r\n\r\nRP/0/RSP1/CPU0:ASR-9906-D#show platform\r\nThu Feb 1 20:18:56.754 UTC\r\nNode              Type                       State             Config state\r\n--------------------------------------------------------------------------------\r\n0/RSP0/CPU0       A9K-RSP5-SE(Standby)       IOS XR RUN        NSHUT\r\n0/RSP1/CPU0       A9K-RSP5-SE(Active)        IOS XR RUN        NSHUT\r\n0/FT0             ASR-9906-FAN               OPERATIONAL       NSHUT\r\n0/FT1             ASR-9906-FAN               OPERATIONAL       NSHUT\r\n0/0/CPU0          A99-32X100GE-X-SE          IOS XR RUN        NSHUT\r\n0/1/CPU0          A99-32X100GE-X-SE          IOS XR RUN        NSHUT\r\n0/2/CPU0          A9K-48X10GE-1G-SE          IOS XR RUN        NSHUT\r\n0/3/CPU0          A99-4HG-FLEX-TR            IOS XR RUN        NSHUT\r\n0/FC0             A99-SFC3-T                 OPERATIONAL       NSHUT\r\n0/FC1             A99-SFC3-T                 OPERATIONAL       NSHUT\r\n0/FC2             A99-SFC3-T                 OPERATIONAL       NSHUT\r\n0/FC4             A99-SFC3-T                 OPERATIONAL       NSHUT\r\n0/PT0             A9K-AC-PEM-V3              OPERATIONAL       NSHUT\r\nRP/0/RSP1/CPU0:ASR-9906-D#\r\n\r\nThe following line cards are Lightspeed-based:\r\n\r\nA9K-16X100GE-TR\r\nA99-16X100GE-X-SE\r\nA99-32X100GE-TR\r\n\r\nThe following line cards are Lightspeed-Plus-based:\r\n\r\nA9K-4HG-FLEX-TR\r\nA9K-4HG-FLEX-SE\r\nA99-4HG-FLEX-TR\r\nA99-4HG-FLEX-SE\r\nA9K-8HG-FLEX-TR\r\nA9K-8HG-FLEX-SE\r\nA9K-20HG-FLEX-TR\r\nA9K-20HG-FLEX-SE\r\nA99-32X100GE-X-TR\r\nA99-32X100GE-X-SE\r\nA99-10X400GE-X-TR\r\nA99-10X400GE-X-SE\r\n\r\nFor more information about line card type identification, see Understand ASR 9000 Series Line Card Types [\"https://www.cisco.com/c/en/us/support/docs/routers/asr-9000-series-aggregation-services-routers/116726-qanda-product-00.html#toc-hId-1632308981\"].\r\n\r\nNote: At the time of publication, the lists of Cisco Lightspeed and Lightspeed-Plus product identifiers (PIDs) were accurate. For specific questions and further clarification about a PID, contact the Cisco Technical Assistance Center (TAC).\r\n\r\nDetermine Whether BNG PPPoE is Enabled Globally\r\n\r\nTo determine whether BNG PPPoE is enabled globally, use the show running-config pppoe bba-group command. If pppoe bba-group is present under the broadband aggregation (BBA) group, as shown in the following example, BNG PPPoE is enabled:\r\n\r\n\r\nRP/0/RSP1/CPU0:ASR-9906-D#show running-config pppoe bba-group\r\nThu Feb 1 21:19:21.003 UTC\r\npppoe bba-group TS-PPPOE\r\nservice selection disable\r\n sessions max limit 32000\r\n!\r\nRP/0/RSP1/CPU0:ASR-9906-D#\r\n\r\nDetermine Whether BNG PPPoE is Enabled on an Interface\r\n\r\n\r\nTo determine whether an interface has BNG PPPoE enabled, use the show running-config interface | utility egrep \"interface|pppoe enable bba-group|bundle id\" command. If pppoe enable bba-group is configured on an interface or sub-interface, BNG PPoE is enabled.\r\n\r\nThe following example shows the output for a device that has the following characteristics:\r\n\r\nInterface Bundle-Ether41.50 has PPPoE enabled.\r\nInterface TenGigE0/3/0/0 is configured as part of Bundle-Ether41.\r\nInterface TenGigE0/3/0/0 is on a Lightspeed-Plus-based line card A99-4HG-FLEX-TR and has PPPoE enabled.\r\n\r\n\r\nRP/0/RSP1/CPU0:ASR-9906-D#show running-config interface | utility egrep \"interface|pppoe enable bba-group|bundle id\"\r\nThu Feb 1 22:12:42.769 UTC\r\ninterface Bundle-Ether20\r\ninterface Bundle-Ether20\r\ninterface Bundle-Ether41\r\ninterface Bundle-Ether41.50\r\n pppoe enable bba-group TS-PPPOE\r\ninterface Bundle-Ether41.55\r\ninterface Loopback0\r\ninterface TenGigE0/3/0/0\r\n bundle id 41 mode on\r\n.\r\n.\r\n.\r\n\r\nNote: For clarity, the preceding output was altered to show fewer interfaces.",
        "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 XE Software\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      Fixed Releases\r\nIn the following table, the left column lists Cisco software releases. The right column indicates whether a release is affected by the vulnerability that is described in this advisory and the first release that includes the fix for this vulnerability. Customers are advised to upgrade to an appropriate fixed software release [\"https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html#fixes\"] as indicated in this section.\r\n        Cisco IOS XR Software Release  First Fixed Release          7.8 and earlier  Migrate to a fixed release.      7.9  7.9.21      7.10  7.10.1      7.11  7.11.1\r\nCisco has released the following SMUs to address this vulnerability.\r\n\r\nNote: Customers who require SMUs for releases that are not listed in the following table are advised to contact their support organization.\r\n\r\n        Cisco IOS XR Software Release  Platform  SMU Name          7.5.2  ASR9K-X64  asr9k-x64-7.5.2.CSCwf75789\r\nThe Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.",
        "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 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 XR Software for ASR 9000 Series Aggregation Services Routers PPPoE Denial of Service Vulnerability",
        "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-pppma-JKWFgneW"
      },
      {
        "category": "external",
        "summary": "Cisco Event Response: March 2024 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication",
        "url": "https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75299"
      },
      {
        "category": "external",
        "summary": "Cisco Security Vulnerability Policy",
        "url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html"
      },
      {
        "category": "external",
        "summary": "Understand ASR 9000 Series Line Card Types",
        "url": "https://www.cisco.com/c/en/us/support/docs/routers/asr-9000-series-aggregation-services-routers/116726-qanda-product-00.html#toc-hId-1632308981"
      },
      {
        "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": "Security Vulnerability Policy",
        "url": "http://www.cisco.com/web/about/security/psirt/security_vulnerability_policy.html"
      }
    ],
    "title": "Cisco IOS XR Software for ASR 9000 Series Aggregation Services Routers PPPoE Denial of Service Vulnerability",
    "tracking": {
      "current_release_date": "2024-03-13T16:00:00+00:00",
      "generator": {
        "date": "2024-05-10T23:29:27+00:00",
        "engine": {
          "name": "TVCE"
        }
      },
      "id": "cisco-sa-iosxr-pppma-JKWFgneW",
      "initial_release_date": "2024-03-13T16:00:00+00:00",
      "revision_history": [
        {
          "date": "2024-03-13T15:56:36+00:00",
          "number": "1.0.0",
          "summary": "Initial public release."
        }
      ],
      "status": "final",
      "version": "1.0.0"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "category": "product_family",
            "name": "Cisco IOS XR Software",
            "product": {
              "name": "Cisco IOS XR Software ",
              "product_id": "CSAFPID-5834"
            }
          }
        ],
        "category": "vendor",
        "name": "Cisco"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2024-20327",
      "ids": [
        {
          "system_name": "Cisco Bug ID",
          "text": "CSCwf75789"
        }
      ],
      "notes": [
        {
          "category": "other",
          "text": "Complete.",
          "title": "Affected Product Comprehensiveness"
        }
      ],
      "product_status": {
        "known_affected": [
          "CSAFPID-5834"
        ]
      },
      "release_date": "2024-03-13T16:00:00+00:00",
      "remediations": [
        {
          "category": "vendor_fix",
          "details": "Cisco has released software updates that address this vulnerability.",
          "product_ids": [
            "CSAFPID-5834"
          ],
          "url": "https://software.cisco.com"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "baseScore": 7.4,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H",
            "version": "3.1"
          },
          "products": [
            "CSAFPID-5834"
          ]
        }
      ],
      "title": "Cisco IOS XR Software for ASR 9000 Series Routers PPPoE Denial of Service Vulnerability"
    }
  ]
}