{
  "document": {
    "acknowledgments": [
      {
        "organization": "Siemens ProductCERT",
        "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",
    "notes": [
      {
        "category": "summary",
        "text": "BACnet ATEC devices are affected by a denial of service vulnerability that could be triggered by an attacker residing in the same BACnet network by sending a specially crafted MSTP message. A power cycle is required to restore the device\u0027s normal operation.\n\nSiemens recommends countermeasures for products where fixes are not, or not yet available.",
        "title": "Summary"
      },
      {
        "category": "general",
        "text": "As a general security measure Siemens strongly recommends to protect network access to affected products with appropriate mechanisms. It is advised to follow recommended security practices in order to run the devices in a protected IT environment.",
        "title": "General Recommendations"
      },
      {
        "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": "legal_disclaimer",
        "text": "The use of Siemens Security Advisories is subject to the terms and conditions listed on: https://www.siemens.com/productcert/terms-of-use.",
        "title": "Terms of Use"
      },
      {
        "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": "other",
        "text": "This ICSA is a verbatim republication of Siemens ProductCERT SSA-828116 from a direct conversion of their vendor\u0027s Common Security Advisory Framework (CSAF) advisory. This is republished to CISA\u0027s website as a means of increasing visibility and is provided \"as-is\" for informational purposes only. CISA is not responsible for the editorial or technical accuracy of republished advisories and provides no warranties of any kind regarding any information contained within this advisory.  Further, CISA does not endorse any commercial product or service.  Please contact Siemens ProductCERT directly for any questions regarding this advisory.",
        "title": "Advisory Conversion Disclaimer"
      },
      {
        "category": "other",
        "text": "Critical Manufacturing, Transportation Systems, Energy, Healthcare and Public Health, Financial Services, Government Services and Facilities",
        "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 exploitation risk of these vulnerabilities.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "Minimize network exposure for all control system devices and/or systems, and ensure they are not accessible from the internet.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "Locate control system networks and remote devices behind firewalls and isolate them from business networks.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most recent version available. Also recognize VPN is only as secure as its connected devices.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets. Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.",
        "title": "Recommended Practices"
      }
    ],
    "publisher": {
      "category": "other",
      "contact_details": "central@cisa.dhs.gov",
      "name": "CISA",
      "namespace": "https://www.cisa.gov/"
    },
    "references": [
      {
        "category": "self",
        "summary": "SSA-828116: Denial of Service Vulnerability in BACnet ATEC Devices - CSAF Version",
        "url": "https://cert-portal.siemens.com/productcert/csaf/ssa-828116.json"
      },
      {
        "category": "self",
        "summary": "SSA-828116: Denial of Service Vulnerability in BACnet ATEC Devices - HTML Version",
        "url": "https://cert-portal.siemens.com/productcert/html/ssa-828116.html"
      },
      {
        "category": "self",
        "summary": "ICS Advisory ICSA-25-135-03 JSON",
        "url": "https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/OT/white/2025/icsa-25-135-03.json"
      },
      {
        "category": "self",
        "summary": "ICS Advisory ICSA-25-135-03 - Web Version",
        "url": "https://www.cisa.gov/news-events/ics-advisories/icsa-25-135-03"
      },
      {
        "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/resources-tools/resources/ics-recommended-practices"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://www.cisa.gov/topics/industrial-control-systems"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://us-cert.cisa.gov/sites/default/files/recommended_practices/NCCIC_ICS-CERT_Defense_in_Depth_2016_S508C.pdf"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://www.cisa.gov/sites/default/files/publications/Cybersecurity_Best_Practices_for_Industrial_Control_Systems.pdf"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://www.cisa.gov/uscert/ics/tips/ICS-TIP-12-146-01B"
      }
    ],
    "title": "Siemens BACnet ATEC Devices",
    "tracking": {
      "current_release_date": "2025-05-13T00:00:00.000000Z",
      "generator": {
        "date": "2025-05-15T17:45:42.420148Z",
        "engine": {
          "name": "CISA CSAF Generator",
          "version": "1.0.0"
        }
      },
      "id": "ICSA-25-135-03",
      "initial_release_date": "2025-05-13T00:00:00.000000Z",
      "revision_history": [
        {
          "date": "2025-05-13T00:00:00.000000Z",
          "legacy_version": "1.0",
          "number": "1",
          "summary": "Publication Date"
        }
      ],
      "status": "final",
      "version": "1"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "vers:all/*",
                "product": {
                  "name": "BACnet ATEC 550-440",
                  "product_id": "CSAFPID-0001"
                }
              }
            ],
            "category": "product_name",
            "name": "BACnet ATEC 550-440"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "vers:all/*",
                "product": {
                  "name": "BACnet ATEC 550-441",
                  "product_id": "CSAFPID-0002"
                }
              }
            ],
            "category": "product_name",
            "name": "BACnet ATEC 550-441"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "vers:all/*",
                "product": {
                  "name": "BACnet ATEC 550-445",
                  "product_id": "CSAFPID-0003"
                }
              }
            ],
            "category": "product_name",
            "name": "BACnet ATEC 550-445"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "vers:all/*",
                "product": {
                  "name": "BACnet ATEC 550-446",
                  "product_id": "CSAFPID-0004"
                }
              }
            ],
            "category": "product_name",
            "name": "BACnet ATEC 550-446"
          }
        ],
        "category": "vendor",
        "name": "Siemens"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2025-40556",
      "cwe": {
        "id": "CWE-20",
        "name": "Improper Input Validation"
      },
      "notes": [
        {
          "category": "summary",
          "text": "Affected devices improperly handle specific incoming BACnet MSTP messages. This could allow an attacker residing in the same BACnet network to send a specially crafted MSTP message that results in a denial of service condition of the targeted device. A power cycle is required to restore the device\u0027s normal operation.",
          "title": "Summary"
        }
      ],
      "product_status": {
        "known_affected": [
          "CSAFPID-0001",
          "CSAFPID-0002",
          "CSAFPID-0003",
          "CSAFPID-0004"
        ]
      },
      "remediations": [
        {
          "category": "no_fix_planned",
          "details": "Currently no fix is planned",
          "product_ids": [
            "CSAFPID-0001",
            "CSAFPID-0002",
            "CSAFPID-0003",
            "CSAFPID-0004"
          ]
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "baseScore": 6.5,
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "products": [
            "CSAFPID-0001",
            "CSAFPID-0002",
            "CSAFPID-0003",
            "CSAFPID-0004"
          ]
        }
      ],
      "title": "CVE-2025-40556"
    }
  ]
}

{
  "affected": [],
  "aliases": [
    "CVE-2025-40556"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-20"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-05-13T10:15:25Z",
    "severity": "HIGH"
  },
  "details": "A vulnerability has been identified in BACnet ATEC 550-440 (All versions), BACnet ATEC 550-441 (All versions), BACnet ATEC 550-445 (All versions), BACnet ATEC 550-446 (All versions). Affected devices improperly handle specific incoming BACnet MSTP messages. This could allow an attacker residing in the same BACnet network to send a specially crafted MSTP message that results in a denial of service condition of the targeted device. A power cycle is required to restore the device\u0027s normal operation.",
  "id": "GHSA-c7rq-qv3j-63j3",
  "modified": "2025-05-13T12:31:36Z",
  "published": "2025-05-13T12:31:36Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-40556"
    },
    {
      "type": "WEB",
      "url": "https://cert-portal.siemens.com/productcert/html/ssa-828116.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}