{
  "document": {
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Disclosure is not limited.",
      "tlp": {
        "label": "WHITE"
      }
    },
    "notes": [
      {
        "category": "summary",
        "text": "The networking component (Nucleus NET) in Nucleus Real-Time Operating System (RTOS) use Initial Sequence Numbers for TCP-Sessions that are predictable.\n\nSiemens has released updates for several affected products and recommends to update to the latest versions. Siemens recommends specific countermeasures for products where updates are not available.",
        "title": "Summary"
      },
      {
        "category": "general",
        "text": "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: \nhttps://www.siemens.com/cert/operational-guidelines-industrial-security), and to follow the recommendations in the product manuals.\nAdditional information on Industrial Security by Siemens can be found at: \nhttps://www.siemens.com/industrialsecurity",
        "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": "Siemens Security Advisories are subject to the terms and conditions contained in Siemens\u0027 underlying license terms or other applicable agreements previously agreed to with Siemens (hereinafter \"License Terms\"). To the extent applicable to information, software or documentation made available in or through a Siemens Security Advisory, the Terms of Use of Siemens\u0027 Global Website (https://www.siemens.com/terms_of_use, hereinafter \"Terms of Use\"), in particular Sections 8-10 of the Terms of Use, shall apply additionally. In case of conflicts, the License Terms shall prevail over the Terms of Use.",
        "title": "Terms of Use"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "productcert@siemens.com",
      "name": "Siemens ProductCERT",
      "namespace": "https://www.siemens.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "SSA-362164: Predictable Initial Sequence Numbers in the TCP/IP Stack of Nucleus RTOS - PDF Version",
        "url": "https://cert-portal.siemens.com/productcert/pdf/ssa-362164.pdf"
      },
      {
        "category": "self",
        "summary": "SSA-362164: Predictable Initial Sequence Numbers in the TCP/IP Stack of Nucleus RTOS - TXT Version",
        "url": "https://cert-portal.siemens.com/productcert/txt/ssa-362164.txt"
      },
      {
        "category": "self",
        "summary": "SSA-362164: Predictable Initial Sequence Numbers in the TCP/IP Stack of Nucleus RTOS - CSAF Version",
        "url": "https://cert-portal.siemens.com/productcert/csaf/ssa-362164.json"
      }
    ],
    "title": "SSA-362164: Predictable Initial Sequence Numbers in the TCP/IP Stack of Nucleus RTOS",
    "tracking": {
      "current_release_date": "2022-11-08T00:00:00Z",
      "generator": {
        "engine": {
          "name": "Siemens ProductCERT CSAF Generator",
          "version": "1"
        }
      },
      "id": "SSA-362164",
      "initial_release_date": "2021-02-09T00:00:00Z",
      "revision_history": [
        {
          "date": "2021-02-09T00:00:00Z",
          "legacy_version": "1.0",
          "number": "1",
          "summary": "Publication Date"
        },
        {
          "date": "2021-11-09T00:00:00Z",
          "legacy_version": "1.1",
          "number": "2",
          "summary": "Consolidated list of products"
        },
        {
          "date": "2022-11-08T00:00:00Z",
          "legacy_version": "1.2",
          "number": "3",
          "summary": "Removed Capital VSTAR as it is not affected by CVE-2022-28388"
        }
      ],
      "status": "final",
      "version": "3"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "\u003c V5.2",
                "product": {
                  "name": "Nucleus NET",
                  "product_id": "1"
                }
              }
            ],
            "category": "product_name",
            "name": "Nucleus NET"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "\u003c V2012.12",
                "product": {
                  "name": "Nucleus ReadyStart V3",
                  "product_id": "2"
                }
              }
            ],
            "category": "product_name",
            "name": "Nucleus ReadyStart V3"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "vers:all/*",
                "product": {
                  "name": "Nucleus Source Code",
                  "product_id": "3"
                }
              }
            ],
            "category": "product_name",
            "name": "Nucleus Source Code"
          }
        ],
        "category": "vendor",
        "name": "Siemens"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2020-28388",
      "cwe": {
        "id": "CWE-342",
        "name": "Predictable Exact Value from Previous Values"
      },
      "notes": [
        {
          "category": "summary",
          "text": "Initial Sequence Numbers (ISNs) for TCP connections are derived from an insufficiently random source. As a result, the ISN of current and future TCP connections could be predictable. An attacker could hijack existing sessions or spoof future ones.\n",
          "title": "Summary"
        }
      ],
      "product_status": {
        "known_affected": [
          "1",
          "2",
          "3"
        ]
      },
      "remediations": [
        {
          "category": "mitigation",
          "details": "Protect transmitted data with cryptographic protocols such as Transport Layer Security",
          "product_ids": [
            "1",
            "2",
            "3"
          ]
        },
        {
          "category": "mitigation",
          "details": "Contact customer support or your local Nucleus Sales team for mitigation advice",
          "product_ids": [
            "1"
          ]
        },
        {
          "category": "mitigation",
          "details": "Note that the latest version of Nucleus NET (V5.2) is not affected, but is already beyond end of software support",
          "product_ids": [
            "1"
          ]
        },
        {
          "category": "mitigation",
          "details": "Update to the latest version of Nucleus ReadyStart V3 or V4",
          "product_ids": [
            "1"
          ]
        },
        {
          "category": "no_fix_planned",
          "details": "Currently no fix is planned",
          "product_ids": [
            "1"
          ]
        },
        {
          "category": "vendor_fix",
          "details": "Update to V2012.12 or later version",
          "product_ids": [
            "2"
          ],
          "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": [
            "3"
          ]
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "baseScore": 6.5,
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L/E:P/RL:O/RC:C",
            "version": "3.1"
          },
          "products": [
            "1",
            "2",
            "3"
          ]
        }
      ],
      "title": "CVE-2020-28388"
    }
  ]
}