{
  "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 IPv6 subsystem of Cisco IOS XR Software Release 5.3.4 for the Cisco Aggregation Services Router (ASR) 9000 Series could allow an unauthenticated, remote attacker to trigger a reload of one or more Trident-based line cards, resulting in a denial of service (DoS) condition.\r\n\r\nThe vulnerability is due to incorrect handling of IPv6 packets with a fragment header extension. An attacker could exploit this vulnerability by sending IPv6 packets designed to trigger the issue either to or through the Trident-based line card. A successful exploit could allow the attacker to trigger a reload of Trident-based line cards, resulting in a DoS during the period of time the line card takes to restart.\r\n\r\nCisco has released software updates that address this vulnerability.  There are no workarounds that address this vulnerability.\r\n\r\n",
        "title": "Summary"
      },
      {
        "category": "general",
        "text": "This vulnerability affects Cisco Aggregation Services Router (ASR) 9000 Series when the following conditions are met:\r\n\r\nThe router is running Cisco IOS XR Software Release 5.3.4.\r\nThe router has installed Trident-based line cards that have IPv6 configured.\r\n  Determining the Cisco IOS XR Software Release\r\n\r\nTo determine which Cisco IOS XR Software release is running on a device and the name of the device on which it is running, administrators can log in to the device and use the show version command in the CLI. If the device is running Cisco IOS XR Software, Cisco IOS XR Software or similar text appears in the system banner. The location and name of the system image file that is currently running on the device appears next to the System image file is text. The name of the hardware product appears on the line after the name of the system image file.\r\n\r\nThe following example shows the output of the show version command on a device that is running Cisco IOS XR Software release 5.3.4:\r\nRP/0/RSP0/CPU0:ASR9001#show version\r\nWed Jan 24 01:32:32.751 EST    Cisco IOS XR Software, Version 5.3.4[Default]  Copyright (c) 2017 by Cisco Systems, Inc.    ROM: System Bootstrap, Version 2.04(20140227:092320) [ASR9K ROMMON],      ASR9001 uptime is 6 hours, 17 minutes  System image file is \"bootflash:disk0/asr9k-os-mbi-5.3.4.sp4-1.0.0/0x100000/mbiasr9k-rp.vm\"    cisco ASR9K Series (P4040) processor with 8388608K bytes of memory.  P4040 processor at 1500MHz, Revision 2.0  ASR-9001 Chassis    2 Management Ethernet  8 TenGigE  20 GigabitEthernet  8 DWDM controller(s)  8 WANPHY controller(s)  44 GigabitEthernet/IEEE 802.3 interface(s)  219k bytes of non-volatile configuration memory.  2880M bytes of hard disk.  3932144k bytes of disk0: (Sector size 512 bytes).    Configuration register on node 0/RSP0/CPU0 is 0x2102\r\n\r\n\r\nDetermining if the Device Has a Trident-based Line Card\r\n\r\nThe first generation of the Cisco ASR 9000 Series Ethernet line cards are often referred to as Trident-based (or Ethernet) line cards. The term comes from the Network Processors (NPs) that are used on these line cards. The following is a complete list of affected Trident-based line cards. Line cards not listed are not affected by this vulnerability:\r\n\r\nA9K-40GE-L\r\nA9K-40GE-B\r\nA9K-40GE-E\r\nA9K-4T-L\r\nA9K-4T-B\r\nA9K-4T-E\r\nA9K-8T/4-L\r\nA9K-8T/4-B\r\nA9K-8T/4-E\r\nA9K-2T20GE-L\r\nA9K-2T20GE-B\r\nA9K-2T20GE-E\r\nA9K-8T-L\r\nA9K-8T-B\r\nA9K-8T-E\r\nA9K-16/8T-B\r\n  To determine whether the line card installed in the ASR 9000 Series Router is Trident-based, the administrator can use the show diag | include PID: command. Affected devices will include the product ID (PID) for at least one of the Trident-based line cards listed previously. The following example shows a device on which an A9K-8T-L card is active:\r\nRP/0/RSP0/CPU0:ASR9006-B#show diag | include PID:\r\nTue Jan 26 00:07:09.406 EST    PID:   A9K-RSP440-SE    PID:   A9K-RSP440-SE    PID:   A9K-8X100GE-SE    PID:   A9K-8T-L    PID:   A9K-36X10GE-SE    PID:   A9K-MOD160-TR    PID:   A9K-MPA-8X10GE     PID:   A9K-MPA-8X10GE   RP/0/RSP0/CPU0:ASR9006-B#\r\n    For more information on Trident-based line cards, consult the ASR 9000 Series Line Card Types publication at the following URL: https://www.cisco.com/c/en/us/support/docs/routers/asr-9000-series-aggregation-services-routers/116726-qanda-product-00.html [\"https://www.cisco.com/c/en/us/support/docs/routers/asr-9000-series-aggregation-services-routers/116726-qanda-product-00.html#anc2\"]\r\n\r\nDetermining if the Device Is Configured for IPv6\r\n\r\nAdministrators can use the show ipv6 interface brief command to determine if an interface is enabled for IPv6 traffic processing. The following example shows an interface configured for IPv6 processing:\r\nRP/0/RP0/CPU0:router# show ipv6 interface brief\r\nGigabitEthernet0/2/0/0 [Up/Up]  fe80::212:daff:fe62:c150  202::1  .\r\n.\r\n.\r\n\r\nThe show ipv6 interface brief command will produce an error message if the running version of Cisco IOS XR Software does not support IPv6. The output will not show any interfaces with IPv6 addresses if IPv6 is disabled.\r\n\r\nAn interface may be configured for IPv6 processing but may not appear on the output of the show ipv6 interface brief command if the interface is part of a bundle or a virtual routing and forwarding (VRF) instance. The show ipv6 vrf all interface command can be used to determine whether any interface has been configured in this way. The following is the output of the show ipv6 vrf all interface command showing an interface configured for IPv6 processing as part of a bundle and assigned to a VRF instance:\r\nRP/0/RP0/CPU0:Router#show ipv6 vrf all interface\r\n.\r\n.\r\n.  Bundle-Ether4.765 is Up, ipv6 protocol is Up, Vrfid is FDA (0x60000001)    IPv6 is enabled, link-local address is fe80::21d:a2ff:aabb:ccdd    Global unicast address(es):      2001:db8:1:1::1, subnet is 2001:db8:1:1::/64     Joined group address(es): ff02::1:ff00:0 ff02::1:aabb:ccdd ff02::2        ff02::1    MTU is 1518 (1500 is available to IPv6)    ICMP redirects are disabled    ICMP unreachables are enabled    ND DAD is enabled, number of DAD attempts 1    ND reachable time is 0 milliseconds    ND advertised retransmit interval is 0 milliseconds    Hosts use stateless autoconfig for addresses.    Outgoing access list is not set    Inbound  access list is not set    Table Id is 0xe0800001",
        "title": "Vulnerable Products"
      },
      {
        "category": "general",
        "text": "No other Cisco products are currently known to be affected by this vulnerability.\r\n\r\nCisco Aggregation Services Router (ASR) 9000 Series that do not contain any Trident-based line cards, are not running Cisco IOS XR Software Release 5.3.4, or are not enabled for IPv6 are not affected.\r\n\r\nNo other devices running Cisco IOS XR Software are affected.",
        "title": "Products Confirmed Not Vulnerable"
      },
      {
        "category": "general",
        "text": "Exploitation of this vulnerability could cause the Trident-based line card to reload and generate error messages similar to the following:\r\nLC/0/6/CPU0:pfm_node_lc[285]: %PLATFORM-DIAGS-0-LC_NP_LOOPBACK_FAILED_RX_PATH : Set|online_diag_lc[163925]|Line card NPU loopback Test(0x2000006)|link failure mask is 0x20.\r\nLC/0/6/CPU0:prm_server_tr[296]: %PLATFORM-NP-0-INIT_ERR : *** Error 0xA0003F03 : prm_np_fast_reset : Channel 5 Config Start Fast Reset failed, line card will be reloaded    LC/0/6/CPU0:prm_server_tr[296]: %PLATFORM-NP-4-FAULT : Line card needs to be reloaded, a reboot is being requested    LC/0/5/CPU0:prm_server_tr[296]: %PLATFORM-NP-0-INIT_ERR : *** Error 0xA0003F03 : prm_np_fast_reset : Channel 5 Config Start Fast Reset failed, line card will be reloaded    LC/0/5/CPU0:prm_server_tr[296]: %PLATFORM-NP-4-FAULT : Line card needs to be reloaded, a reboot is being requested     LC/0/5/CPU0:syslog_dev[88]: prm_server_tr[296] PID-163922: reboot internal start: cause code 27 cause Fast Reset of the NP failed, LC reboot needed to recover the NP\r\n  For a final confirmation on whether these message do indeed indicate exploitation of this issue, please contact your support organization.",
        "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  A software maintenance upgrade (SMU) has been made available that addresses this vulnerability. The fix has also been incorporated into service pack 7 for Cisco IOS XR Software Release 5.3.4.\r\n\r\n                              IOS XR Release              SMU ID              SMU/Service Pack Name                                   5.3.4              AA13804              asr9k-px-5.3.4.CSCvg46800.tar [\"https://software.cisco.com/download/release.html%3Fmdfid%3D282414851%26softwareid%3D280867577%26release%3D5.3.4\"]                                   5.3.4              AA13870              asr9k-px.5.3.4.sp7.tar [\"https://software.cisco.com/download/release.html?mdfid=282414851\u0026softwareid=286224007\u0026release=5.3.4\"]\r\nThe SMU/service pack can be downloaded from the Software Center [\"https://software.cisco.com/download/navigator.html\"] on Cisco.com by navigating to the IOS XR Software Maintenance Upgrades (SMU)-5.3.4 or IOS XR Service Packs-5.3.4 respectively.",
        "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": "psirt@cisco.com",
      "issuing_authority": "Cisco PSIRT",
      "name": "Cisco",
      "namespace": "https://wwww.cisco.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "Cisco Aggregation Services Router 9000 Series IPv6 Fragment Header Denial of Service Vulnerability",
        "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180131-ipv6"
      },
      {
        "category": "external",
        "summary": "Cisco Security Vulnerability Policy",
        "url": "https://sec.cloudapps.cisco.com/security/center/resources/security_vulnerability_policy.html"
      },
      {
        "category": "external",
        "summary": "https://www.cisco.com/c/en/us/support/docs/routers/asr-9000-series-aggregation-services-routers/116726-qanda-product-00.html",
        "url": "https://www.cisco.com/c/en/us/support/docs/routers/asr-9000-series-aggregation-services-routers/116726-qanda-product-00.html#anc2"
      },
      {
        "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": "asr9k-px-5.3.4.CSCvg46800.tar",
        "url": "https://software.cisco.com/download/release.html%3Fmdfid%3D282414851%26softwareid%3D280867577%26release%3D5.3.4"
      },
      {
        "category": "external",
        "summary": "asr9k-px.5.3.4.sp7.tar",
        "url": "https://software.cisco.com/download/release.html?mdfid=282414851\u0026amp;softwareid=286224007\u0026amp;release=5.3.4"
      },
      {
        "category": "external",
        "summary": "Software Center",
        "url": "https://software.cisco.com/download/navigator.html"
      }
    ],
    "title": "Cisco Aggregation Services Router 9000 Series IPv6 Fragment Header Denial of Service Vulnerability",
    "tracking": {
      "current_release_date": "2018-01-31T16:00:00+00:00",
      "generator": {
        "date": "2024-05-10T22:45:38+00:00",
        "engine": {
          "name": "TVCE"
        }
      },
      "id": "cisco-sa-20180131-ipv6",
      "initial_release_date": "2018-01-31T16:00:00+00:00",
      "revision_history": [
        {
          "date": "2018-01-31T15:04:25+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": "product_family",
            "name": "Cisco ASR 9000 Series Aggregation Services Routers",
            "product": {
              "name": "Cisco ASR 9000 Series Aggregation Services Routers ",
              "product_id": "CSAFPID-202356"
            }
          }
        ],
        "category": "vendor",
        "name": "Cisco"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2018-0136",
      "ids": [
        {
          "system_name": "Cisco Bug ID",
          "text": "CSCvg46800"
        }
      ],
      "notes": [
        {
          "category": "other",
          "text": "Complete.",
          "title": "Affected Product Comprehensiveness"
        }
      ],
      "product_status": {
        "known_affected": [
          "CSAFPID-202356",
          "CSAFPID-5834"
        ]
      },
      "release_date": "2018-01-31T16:00:00+00:00",
      "remediations": [
        {
          "category": "vendor_fix",
          "details": "Cisco has released software updates that address this vulnerability.",
          "product_ids": [
            "CSAFPID-5834",
            "CSAFPID-202356"
          ],
          "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-202356",
            "CSAFPID-5834"
          ]
        }
      ],
      "title": "Cisco Aggregation Services Router 9000 Series IPv6 Fragment Header Denial of Service Vulnerability"
    }
  ]
}