{
  "document": {
    "acknowledgments": [
      {
        "organization": "Siemens ProductCERT",
        "summary": "reporting this vulnerability to NCCIC"
      }
    ],
    "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 cause a denial-of-service condition of the CPU. The CPU will remain in DEFECT mode until a manual restart is performed.",
        "title": "Risk evaluation"
      },
      {
        "category": "other",
        "text": "Chemical, Critical Manufacturing, Energy, Food and Agriculture, Water and Wastewater Systems",
        "title": "Critical infrastructure sectors"
      },
      {
        "category": "other",
        "text": "Worldwide",
        "title": "Countries/areas deployed"
      },
      {
        "category": "other",
        "text": "Germany",
        "title": "Company headquarters location"
      },
      {
        "category": "general",
        "text": "NCCIC recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "NCCIC reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "NCCIC also provides a section for control systems security recommended practices on the ICS-CERT web page. 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": "Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to NCCIC for tracking and correlation against other incidents.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "Additional mitigation guidance and recommended practices are publicly available on the ICS-CERT website in the Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "For further inquiries on security vulnerabilities in Siemens products and \nsolutions, please contact the Siemens ProductCERT:\n\nhttps://www.siemens.com/cert/advisories",
        "title": "Additional Resources"
      },
      {
        "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": "self",
        "summary": "ICS Advisory ICSA-18-137-03 JSON",
        "url": "https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/OT/white/2018/icsa-18-137-03.json"
      },
      {
        "category": "self",
        "summary": "ICS Advisory ICSA-18-137-03 Web Version",
        "url": "https://www.cisa.gov/news-events/ics-advisories/icsa-18-137-03"
      },
      {
        "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/news-events/ics-advisories/icsa-18-137-03"
      },
      {
        "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": "SSA-496604: SSA-914382: Denial-of-Service Vulnerability in SIMATIC S7-400 CPU Family - TXT Version",
        "url": "https://cert-portal.siemens.com/productcert/txt/SSA-914382.txt"
      }
    ],
    "title": "Siemens SIMATIC S7-400 CPU (Update A)",
    "tracking": {
      "current_release_date": "2018-09-11T00:00:00.000000Z",
      "generator": {
        "engine": {
          "name": "CISA CSAF Generator",
          "version": "1.0.0"
        }
      },
      "id": "ICSA-18-137-03",
      "initial_release_date": "2018-05-17T00:00:00.000000Z",
      "revision_history": [
        {
          "date": "2018-05-17T00:00:00.000000Z",
          "legacy_version": "Initial",
          "number": "1",
          "summary": "ICSA-18-137-03 Siemens SIMATIC S7-400 CPU"
        },
        {
          "date": "2018-09-11T00:00:00.000000Z",
          "legacy_version": "A",
          "number": "2",
          "summary": "ICSA-18-137-03 Siemens SIMATIC S7-400 CPU (Update A)"
        }
      ],
      "status": "final",
      "version": "2"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "All versions",
                "product": {
                  "name": "SIMATIC S7-400 CPU hardware version 4.0 and below (incl. SIPLUS: All versions",
                  "product_id": "CSAFPID-0001"
                }
              }
            ],
            "category": "product_name",
            "name": "SIMATIC S7-400 CPU hardware version 4.0 and below (incl. SIPLUS"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "All firmware versions \u003c V5.2",
                "product": {
                  "name": "SIMATIC S7-400 CPU hardware version 5.0 (incl. SIPLUS variants): All firmware versions \u003c V5.2",
                  "product_id": "CSAFPID-0002"
                }
              }
            ],
            "category": "product_name",
            "name": "SIMATIC S7-400 CPU hardware version 5.0 (incl. SIPLUS variants)"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "All versions",
                "product": {
                  "name": "SIMATIC S7-400 H CPU hardware version 4.5 and below (incl. SIPLUS: All versions",
                  "product_id": "CSAFPID-0003"
                }
              }
            ],
            "category": "product_name",
            "name": "SIMATIC S7-400 H CPU hardware version 4.5 and below (incl. SIPLUS"
          }
        ],
        "category": "vendor",
        "name": "Siemens"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2018-4850",
      "cwe": {
        "id": "CWE-20",
        "name": "Improper Input Validation"
      },
      "notes": [
        {
          "category": "summary",
          "text": "The affected CPUs improperly validate S7 communication packets which could cause a Denial-of-Service condition of the CPU. The CPU will remain in DEFECT mode until manual restart.",
          "title": "Summary"
        },
        {
          "category": "summary",
          "text": "Successful exploitation requires an attacker to be able to send a specially crafted S7 communication packet to a communication interface of the CPU. This includes Ethernet, PROFIBUS, and Multi Point Interfaces (MPI). No user interaction or privileges are required to exploit the security vulnerability. The vulnerability could allow causing a Denial-of-Service condition of the core functionality of the CPU, compromising the availability of the system.",
          "title": "Summary"
        },
        {
          "category": "summary",
          "text": "At the time of advisory publication no public exploitation of this security vulnerability was known. Siemens confirms the security vulnerability and provides mitigations to resolve the security issue.",
          "title": "Summary"
        }
      ],
      "product_status": {
        "known_affected": [
          "CSAFPID-0001",
          "CSAFPID-0002",
          "CSAFPID-0003"
        ]
      },
      "references": [
        {
          "category": "external",
          "summary": "https://support.industry.siemens.com/cs/ww/en/view/75407031",
          "url": "https://support.industry.siemens.com/cs/ww/en/view/75407031"
        },
        {
          "category": "external",
          "summary": "web.nvd.nist.gov",
          "url": "http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2018-4850"
        },
        {
          "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:N/A:H"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "details": "Apply cell protection concept:\nhttps://www.siemens.com/cert/operational-guidelines-industrial-security.",
          "product_ids": [
            "CSAFPID-0001",
            "CSAFPID-0002",
            "CSAFPID-0003"
          ]
        },
        {
          "category": "vendor_fix",
          "details": "Use VPN for protecting network communication between cells.",
          "product_ids": [
            "CSAFPID-0001",
            "CSAFPID-0002",
            "CSAFPID-0003"
          ]
        },
        {
          "category": "vendor_fix",
          "details": "Apply Defense-in-Depth:\nhttps://www.siemens.com/cert/operational-guidelines-industrial-security.",
          "product_ids": [
            "CSAFPID-0001",
            "CSAFPID-0002",
            "CSAFPID-0003"
          ]
        },
        {
          "category": "vendor_fix",
          "details": "See recommendations from section Workarounds and Mitigations or upgrade to hardware version 5.0 or newer - Download: https://support.industry.siemens.com/cs/ww/en/view/109483507 ",
          "product_ids": [
            "CSAFPID-0001"
          ],
          "url": "https://support.industry.siemens.com/cs/ww/en/view/109483507"
        },
        {
          "category": "vendor_fix",
          "details": "Update to firmware version 5.2 or newer - Download: https://support.industry.siemens.com/cs/ww/en/view/109474827 ",
          "product_ids": [
            "CSAFPID-0002"
          ],
          "url": "https://support.industry.siemens.com/cs/ww/en/view/109474827"
        },
        {
          "category": "vendor_fix",
          "details": "See recommendations from section Workarounds and Mitigations or upgrade to hardware version 6.0 or newer - Download: https://support.industry.siemens.com/cs/ww/en/view/75407031 ",
          "product_ids": [
            "CSAFPID-0003"
          ],
          "url": "https://support.industry.siemens.com/cs/ww/en/view/75407031"
        },
        {
          "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. Additional 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": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C",
            "version": "3.1"
          },
          "products": [
            "CSAFPID-0001",
            "CSAFPID-0002",
            "CSAFPID-0003"
          ]
        }
      ]
    }
  ]
}