FKIE_CVE-2021-36369

Vulnerability from fkie_nvd - Published: 2022-10-12 21:15 - Updated: 2025-05-15 19:15
Severity ?
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Summary
An issue was discovered in Dropbear through 2020.81. Due to a non-RFC-compliant check of the available authentication methods in the client-side SSH code, it is possible for an SSH server to change the login process in its favor. This attack can bypass additional security measures such as FIDO2 tokens or SSH-Askpass. Thus, it allows an attacker to abuse a forwarded agent for logging on to another server unnoticed.
References
cve@mitre.orghttps://github.com/mkj/dropbear/pull/128Third Party Advisory
cve@mitre.orghttps://github.com/mkj/dropbear/releasesRelease Notes, Third Party Advisory
cve@mitre.orghttps://github.com/mkj/dropbear/releases/tag/DROPBEAR_2022.82Release Notes, Third Party Advisory
cve@mitre.orghttps://lists.debian.org/debian-lts-announce/2022/11/msg00015.htmlMailing List, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://github.com/mkj/dropbear/pull/128Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://github.com/mkj/dropbear/releasesRelease Notes, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://github.com/mkj/dropbear/releases/tag/DROPBEAR_2022.82Release Notes, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2022/11/msg00015.htmlMailing List, Third Party Advisory
Impacted products
Vendor Product Version
dropbear_ssh_project dropbear_ssh *
debian debian_linux 10.0
To clipboard 

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:dropbear_ssh_project:dropbear_ssh:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "28DDCDD1-0D7D-47ED-AC09-6E7B1E2FA1A1",
              "versionEndIncluding": "2020.81",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    },
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*",
              "matchCriteriaId": "07B237A9-69A3-4A9C-9DA0-4E06BD37AE73",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "An issue was discovered in Dropbear through 2020.81. Due to a non-RFC-compliant check of the available authentication methods in the client-side SSH code, it is possible for an SSH server to change the login process in its favor. This attack can bypass additional security measures such as FIDO2 tokens or SSH-Askpass. Thus, it allows an attacker to abuse a forwarded agent for logging on to another server unnoticed."
    },
    {
      "lang": "es",
      "value": "Se ha detectado un problema en Dropbear versiones hasta 2020.81. Debido a una comprobaci\u00f3n no compatible con RFC de los m\u00e9todos de autenticaci\u00f3n disponibles en el c\u00f3digo SSH del lado del cliente, es posible que un servidor SSH cambie el proceso de inicio de sesi\u00f3n a su favor. Este ataque puede omitir medidas de seguridad adicionales como los tokens FIDO2 o SSH-Askpass. Por lo tanto, permite a un atacante abusar de un agente reenviado para iniciar sesi\u00f3n en otro servidor de forma inadvertida"
    }
  ],
  "id": "CVE-2021-36369",
  "lastModified": "2025-05-15T19:15:53.450",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "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,
        "source": "nvd@nist.gov",
        "type": "Primary"
      },
      {
        "cvssData": {
          "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,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ]
  },
  "published": "2022-10-12T21:15:09.493",
  "references": [
    {
      "source": "cve@mitre.org",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://github.com/mkj/dropbear/pull/128"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Release Notes",
        "Third Party Advisory"
      ],
      "url": "https://github.com/mkj/dropbear/releases"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Release Notes",
        "Third Party Advisory"
      ],
      "url": "https://github.com/mkj/dropbear/releases/tag/DROPBEAR_2022.82"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Mailing List",
        "Third Party Advisory"
      ],
      "url": "https://lists.debian.org/debian-lts-announce/2022/11/msg00015.html"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://github.com/mkj/dropbear/pull/128"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Release Notes",
        "Third Party Advisory"
      ],
      "url": "https://github.com/mkj/dropbear/releases"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Release Notes",
        "Third Party Advisory"
      ],
      "url": "https://github.com/mkj/dropbear/releases/tag/DROPBEAR_2022.82"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Mailing List",
        "Third Party Advisory"
      ],
      "url": "https://lists.debian.org/debian-lts-announce/2022/11/msg00015.html"
    }
  ],
  "sourceIdentifier": "cve@mitre.org",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-287"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    },
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-287"
        }
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary"
    }
  ]
}


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