gsd-2020-27213
Vulnerability from gsd
Modified
2023-12-13 01:22
Details
An issue was discovered in Ethernut Nut/OS 5.1. The code that generates Initial Sequence Numbers (ISNs) for TCP connections derives the ISN from an insufficiently random source. As a result, an attacker may be able to determine the ISN of current and future TCP connections and either hijack existing ones or spoof future ones. While the ISN generator seems to adhere to RFC 793 (where a global 32-bit counter is incremented roughly every 4 microseconds), proper ISN generation should aim to follow at least the specifications outlined in RFC 6528.
Aliases
Aliases
CVE-2020-27213


To clipboard 

{
  "GSD": {
    "alias": "CVE-2020-27213",
    "id": "GSD-2020-27213"
  },
  "gsd": {
    "metadata": {
      "exploitCode": "unknown",
      "remediation": "unknown",
      "reportConfidence": "confirmed",
      "type": "vulnerability"
    },
    "osvSchema": {
      "aliases": [
        "CVE-2020-27213"
      ],
      "details": "An issue was discovered in Ethernut Nut/OS 5.1. The code that generates Initial Sequence Numbers (ISNs) for TCP connections derives the ISN from an insufficiently random source. As a result, an attacker may be able to determine the ISN of current and future TCP connections and either hijack existing ones or spoof future ones. While the ISN generator seems to adhere to RFC 793 (where a global 32-bit counter is incremented roughly every 4 microseconds), proper ISN generation should aim to follow at least the specifications outlined in RFC 6528.",
      "id": "GSD-2020-27213",
      "modified": "2023-12-13T01:22:11.409588Z",
      "schema_version": "1.4.0"
    }
  },
  "namespaces": {
    "cve.org": {
      "CVE_data_meta": {
        "ASSIGNER": "cve@mitre.org",
        "ID": "CVE-2020-27213",
        "STATE": "PUBLIC"
      },
      "affects": {
        "vendor": {
          "vendor_data": [
            {
              "product": {
                "product_data": [
                  {
                    "product_name": "n/a",
                    "version": {
                      "version_data": [
                        {
                          "version_value": "n/a"
                        }
                      ]
                    }
                  }
                ]
              },
              "vendor_name": "n/a"
            }
          ]
        }
      },
      "data_format": "MITRE",
      "data_type": "CVE",
      "data_version": "4.0",
      "description": {
        "description_data": [
          {
            "lang": "eng",
            "value": "An issue was discovered in Ethernut Nut/OS 5.1. The code that generates Initial Sequence Numbers (ISNs) for TCP connections derives the ISN from an insufficiently random source. As a result, an attacker may be able to determine the ISN of current and future TCP connections and either hijack existing ones or spoof future ones. While the ISN generator seems to adhere to RFC 793 (where a global 32-bit counter is incremented roughly every 4 microseconds), proper ISN generation should aim to follow at least the specifications outlined in RFC 6528."
          }
        ]
      },
      "problemtype": {
        "problemtype_data": [
          {
            "description": [
              {
                "lang": "eng",
                "value": "n/a"
              }
            ]
          }
        ]
      },
      "references": {
        "reference_data": [
          {
            "name": "http://www.ethernut.de/en/download/index.html",
            "refsource": "MISC",
            "url": "http://www.ethernut.de/en/download/index.html"
          },
          {
            "name": "http://lists.egnite.de/mailman/listinfo/en-nut-announce",
            "refsource": "MISC",
            "url": "http://lists.egnite.de/mailman/listinfo/en-nut-announce"
          },
          {
            "name": "https://www.cisa.gov/news-events/ics-advisories/icsa-21-042-01",
            "refsource": "MISC",
            "url": "https://www.cisa.gov/news-events/ics-advisories/icsa-21-042-01"
          },
          {
            "name": "https://www.forescout.com/resources/numberjack-weak-isn-generation-in-embedded-tcpip-stacks/",
            "refsource": "MISC",
            "url": "https://www.forescout.com/resources/numberjack-weak-isn-generation-in-embedded-tcpip-stacks/"
          }
        ]
      }
    },
    "nvd.nist.gov": {
      "configurations": {
        "CVE_data_version": "4.0",
        "nodes": [
          {
            "children": [],
            "cpe_match": [
              {
                "cpe23Uri": "cpe:2.3:o:ethernut:nut\\/os:5.1:*:*:*:*:*:*:*",
                "cpe_name": [],
                "vulnerable": true
              }
            ],
            "operator": "OR"
          }
        ]
      },
      "cve": {
        "CVE_data_meta": {
          "ASSIGNER": "cve@mitre.org",
          "ID": "CVE-2020-27213"
        },
        "data_format": "MITRE",
        "data_type": "CVE",
        "data_version": "4.0",
        "description": {
          "description_data": [
            {
              "lang": "en",
              "value": "An issue was discovered in Ethernut Nut/OS 5.1. The code that generates Initial Sequence Numbers (ISNs) for TCP connections derives the ISN from an insufficiently random source. As a result, an attacker may be able to determine the ISN of current and future TCP connections and either hijack existing ones or spoof future ones. While the ISN generator seems to adhere to RFC 793 (where a global 32-bit counter is incremented roughly every 4 microseconds), proper ISN generation should aim to follow at least the specifications outlined in RFC 6528."
            }
          ]
        },
        "problemtype": {
          "problemtype_data": [
            {
              "description": [
                {
                  "lang": "en",
                  "value": "CWE-330"
                }
              ]
            }
          ]
        },
        "references": {
          "reference_data": [
            {
              "name": "http://www.ethernut.de/en/download/index.html",
              "refsource": "MISC",
              "tags": [
                "Release Notes"
              ],
              "url": "http://www.ethernut.de/en/download/index.html"
            },
            {
              "name": "https://www.cisa.gov/news-events/ics-advisories/icsa-21-042-01",
              "refsource": "MISC",
              "tags": [
                "Third Party Advisory",
                "US Government Resource"
              ],
              "url": "https://www.cisa.gov/news-events/ics-advisories/icsa-21-042-01"
            },
            {
              "name": "http://lists.egnite.de/mailman/listinfo/en-nut-announce",
              "refsource": "MISC",
              "tags": [
                "Not Applicable"
              ],
              "url": "http://lists.egnite.de/mailman/listinfo/en-nut-announce"
            },
            {
              "name": "https://www.forescout.com/resources/numberjack-weak-isn-generation-in-embedded-tcpip-stacks/",
              "refsource": "MISC",
              "tags": [
                "Exploit",
                "Third Party Advisory"
              ],
              "url": "https://www.forescout.com/resources/numberjack-weak-isn-generation-in-embedded-tcpip-stacks/"
            }
          ]
        }
      },
      "impact": {
        "baseMetricV3": {
          "cvssV3": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
            "version": "3.1"
          },
          "exploitabilityScore": 3.9,
          "impactScore": 3.6
        }
      },
      "lastModifiedDate": "2023-10-27T19:34Z",
      "publishedDate": "2023-10-10T17:15Z"
    }
  }
}


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