{
  "document": {
    "acknowledgments": [
      {
        "organization": "Siemens",
        "summary": "reporting this vulnerability to CISA"
      }
    ],
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Disclosure is not limited",
      "tlp": {
        "label": "WHITE",
        "url": "https://us-cert.cisa.gov/tlp/"
      }
    },
    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "This CSAF advisory was extracted from unstructured data and may contain inaccuracies. If you notice any errors, please reach out to the designated contact at CISA CSAF: central@cisa.dhs.gov",
        "title": "CISA Disclaimer"
      },
      {
        "category": "legal_disclaimer",
        "text": "All information products included in https://us-cert.cisa.gov/ics are provided \"as is\" for informational purposes only. The Department of Homeland Security (DHS) does not provide any warranties of any kind regarding any information contained within. DHS does not endorse any commercial product or service, referenced in this product or otherwise. Further dissemination of this product is governed by the Traffic Light Protocol (TLP) marking in the header. For more information about TLP, see https://us-cert.cisa.gov/tlp/.",
        "title": "Legal Notice"
      },
      {
        "category": "summary",
        "text": "Successful exploitation of this vulnerability could allow an attacker to poison the DNS cache or spoof DNS resolving.",
        "title": "Risk evaluation"
      },
      {
        "category": "other",
        "text": "Critical Manufacturing",
        "title": "Critical infrastructure sectors"
      },
      {
        "category": "other",
        "text": "Worldwide",
        "title": "Countries/areas deployed"
      },
      {
        "category": "other",
        "text": "Germany",
        "title": "Company headquarters location"
      },
      {
        "category": "general",
        "text": "CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.\nCISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "Additional mitigation guidance and recommended practices are publicly available on the ICS webpage on cisa.gov in the Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.\nOrganizations observing any suspected malicious activity should follow their established internal procedures and report their findings to CISA for tracking and correlation against other incidents.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "For further inquiries on security vulnerabilities in Siemens products and solutions, please contact the Siemens ProductCERT: https://www.siemens.com/cert/advisories",
        "title": "Additional Resources"
      },
      {
        "category": "other",
        "text": "No known public exploits specifically target this vulnerability.",
        "title": "Exploitability"
      }
    ],
    "publisher": {
      "category": "coordinator",
      "contact_details": "Email: CISAservicedesk@cisa.dhs.gov;\n Toll Free: 1-888-282-0870",
      "name": "CISA",
      "namespace": "https://www.cisa.gov/"
    },
    "references": [
      {
        "category": "external",
        "summary": "SSA-201384: Predictable UDP Port Number Vulnerability (NAME:WRECK) in the DNS Module of Nucleus RTOS - CSAF Version",
        "url": "https://cert-portal.siemens.com/productcert/csaf/ssa-201384.json"
      },
      {
        "category": "self",
        "summary": "ICS Advisory ICSA-21-103-14 JSON",
        "url": "https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/OT/white/2021/icsa-21-103-14.json"
      },
      {
        "category": "self",
        "summary": "ICS Advisory ICSA-21-103-14 Web Version",
        "url": "https://www.cisa.gov/news-events/ics-advisories/icsa-21-103-14"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://www.cisa.gov/uscert/ics/alerts/ICS-ALERT-10-301-01"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://www.cisa.gov/uscert/sites/default/files/recommended_practices/NCCIC_ICS-CERT_Defense_in_Depth_2016_S508C.pdf"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://www.cisa.gov/uscert/ics/tips/ICS-TIP-12-146-01B"
      },
      {
        "category": "external",
        "summary": "SSA-201384: Predictable UDP Port Number Vulnerability (NAME:WRECK) in the DNS Module of Nucleus RTOS - PDF Version",
        "url": "https://cert-portal.siemens.com/productcert/pdf/ssa-201384.pdf"
      },
      {
        "category": "external",
        "summary": "SSA-201384: Predictable UDP Port Number Vulnerability (NAME:WRECK) in the DNS Module of Nucleus RTOS - TXT Version",
        "url": "https://cert-portal.siemens.com/productcert/txt/ssa-201384.txt"
      }
    ],
    "title": "Siemens Nucleus DNS (Update A)",
    "tracking": {
      "current_release_date": "2022-01-13T00:00:00.000000Z",
      "generator": {
        "engine": {
          "name": "CISA CSAF Generator",
          "version": "1.0.0"
        }
      },
      "id": "ICSA-21-103-14",
      "initial_release_date": "2021-04-13T00:00:00.000000Z",
      "revision_history": [
        {
          "date": "2021-04-13T00:00:00.000000Z",
          "legacy_version": "Initial",
          "number": "1",
          "summary": "ICSA-21-103-14 Siemens Nucleus DNS"
        },
        {
          "date": "2022-01-13T00:00:00.000000Z",
          "legacy_version": "A",
          "number": "2",
          "summary": "ICSA-21-103-14 Siemens Nucleus DNS (Update A)"
        }
      ],
      "status": "final",
      "version": "2"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "vers:all/*",
                "product": {
                  "name": "Nucleus NET",
                  "product_id": "CSAFPID-0001"
                }
              }
            ],
            "category": "product_name",
            "name": "Nucleus NET"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "\u003c V2013.08",
                "product": {
                  "name": "Nucleus ReadyStart V3",
                  "product_id": "CSAFPID-0002"
                }
              }
            ],
            "category": "product_name",
            "name": "Nucleus ReadyStart V3"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "Versions including affected DNS modules",
                "product": {
                  "name": "Nucleus Source Code",
                  "product_id": "CSAFPID-0003"
                }
              }
            ],
            "category": "product_name",
            "name": "Nucleus Source Code"
          }
        ],
        "category": "vendor",
        "name": "Siemens"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2021-27393",
      "cwe": {
        "id": "CWE-330",
        "name": "Use of Insufficiently Random Values"
      },
      "notes": [
        {
          "category": "summary",
          "text": "The DNS client does not properly randomize UDP port numbers of DNS requests. That could allow an attacker to poison the DNS cache or spoof DNS resolving.",
          "title": "Summary"
        }
      ],
      "product_status": {
        "known_affected": [
          "CSAFPID-0001",
          "CSAFPID-0002",
          "CSAFPID-0003"
        ]
      },
      "references": [
        {
          "summary": "CVE-2021-27393 - Nucleus ReadyStart V3",
          "url": "https://support.sw.siemens.com/en-US/product/1009925838/"
        },
        {
          "summary": "CVE-2021-27393 Mitre 5.0 json",
          "url": "https://cert-portal.siemens.com/productcert/mitre/CVE-2021-27393.json"
        },
        {
          "category": "external",
          "summary": "web.nvd.nist.gov",
          "url": "http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-27393"
        },
        {
          "category": "external",
          "summary": "www.first.org",
          "url": "https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"
        }
      ],
      "remediations": [
        {
          "category": "mitigation",
          "details": "Update to the latest version of Nucleus ReadyStart V3 or V4",
          "product_ids": [
            "CSAFPID-0001"
          ]
        },
        {
          "category": "mitigation",
          "details": "Contact customer support or your local Nucleus Sales team for mitigation advice",
          "product_ids": [
            "CSAFPID-0001"
          ]
        },
        {
          "category": "no_fix_planned",
          "details": "Currently no remediation is planned",
          "product_ids": [
            "CSAFPID-0001"
          ]
        },
        {
          "category": "vendor_fix",
          "details": "Update to V2013.08 or later version",
          "product_ids": [
            "CSAFPID-0002"
          ],
          "url": "https://support.sw.siemens.com/en-US/product/1009925838/"
        },
        {
          "category": "vendor_fix",
          "details": "Contact customer support to receive patch and update information",
          "product_ids": [
            "CSAFPID-0003"
          ]
        },
        {
          "category": "mitigation",
          "details": "Avoid using DNS client of affected versions",
          "product_ids": [
            "CSAFPID-0001",
            "CSAFPID-0002",
            "CSAFPID-0003"
          ]
        },
        {
          "category": "mitigation",
          "details": "As a general security measure, Siemens strongly recommends to protect network access to devices with appropriate mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends to configure the environment according to Siemens\u0027 operational guidelines for Industrial Security (Download: https://www.siemens.com/cert/operational-guidelines-industrial-security), and to follow the recommendations in the product manuals.\n\nAdditional information on Industrial Security by Siemens can be found at: https://www.siemens.com/industrialsecurity",
          "product_ids": [
            "CSAFPID-0001",
            "CSAFPID-0002",
            "CSAFPID-0003"
          ]
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:P/RL:O/RC:C",
            "version": "3.1"
          },
          "products": [
            "CSAFPID-0001",
            "CSAFPID-0002",
            "CSAFPID-0003"
          ]
        }
      ],
      "title": "CVE-2021-27393"
    }
  ]
}