« Volver al listado

CVE-2020-8831

Estado: ModificadaMedia (5.5)—

Apport creates a world writable lock file with root ownership in the world writable /var/lock/apport directory. If the apport/ directory does not exist (this is not uncommon as /var/lock is a tmpfs), it will create the directory, otherwise it will simply continue execution using the existing directory. This allows for a symlink attack if an attacker were to create a symlink at /var/lock/apport, changing apport's lock file location. This file could then be used to escalate privileges, for example. Fixed in versions 2.20.1-0ubuntu2.23, 2.20.9-0ubuntu7.14, 2.20.11-0ubuntu8.8 and 2.20.11-0ubuntu22.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (2)

Apport Project — ApportCanonical — Ubuntu Linux

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2020-8831",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 2.1,
          "accessVector": "LOCAL",
          "vectorString": "AV:L/AC:L/Au:N/C:N/I:P/A:N",
          "authentication": "NONE",
          "integrityImpact": "PARTIAL",
          "accessComplexity": "LOW",
          "availabilityImpact": "NONE",
          "confidentialityImpact": "NONE"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "LOW",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 3.9,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security@ubuntu.com",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 6.5,
          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 4,
        "exploitabilityScore": 2
      },
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.5,
          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "security@ubuntu.com",
      "affectedData": [
        {
          "vendor": "Canonical",
          "product": "Apport",
          "versions": [
            {
              "status": "affected",
              "version": "2.20.1",
              "lessThan": "2.20.1-0ubuntu2.23",
              "versionType": "custom"
            },
            {
              "status": "affected",
              "version": "2.20.9",
              "lessThan": "2.20.9-0ubuntu7.14",
              "versionType": "custom"
            },
            {
              "status": "affected",
              "changes": [
                {
                  "at": "2.20.11-0ubuntu22",
                  "status": "unaffected"
                }
              ],
              "version": "2.20.11",
              "lessThan": "2.20.11-0ubuntu8.8",
              "versionType": "custom"
            }
          ]
        }
      ]
    }
  ],
  "published": "2020-04-22T22:15:12.513",
  "references": [
    {
      "url": "https://launchpad.net/bugs/1862348",
      "tags": [
        "Exploit",
        "Third Party Advisory"
      ],
      "source": "security@ubuntu.com"
    },
    {
      "url": "https://usn.ubuntu.com/4315-1/",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "security@ubuntu.com"
    },
    {
      "url": "https://usn.ubuntu.com/4315-2/",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "security@ubuntu.com"
    },
    {
      "url": "https://launchpad.net/bugs/1862348",
      "tags": [
        "Exploit",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://usn.ubuntu.com/4315-1/",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://usn.ubuntu.com/4315-2/",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security@ubuntu.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-379"
        }
      ]
    },
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-59"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Apport creates a world writable lock file with root ownership in the world writable /var/lock/apport directory. If the apport/ directory does not exist (this is not uncommon as /var/lock is a tmpfs), it will create the directory, otherwise it will simply continue execution using the existing directory. This allows for a symlink attack if an attacker were to create a symlink at /var/lock/apport, changing apport's lock file location. This file could then be used to escalate privileges, for example. Fixed in versions 2.20.1-0ubuntu2.23, 2.20.9-0ubuntu7.14, 2.20.11-0ubuntu8.8 and 2.20.11-0ubuntu22."
    },
    {
      "lang": "es",
      "value": "Apport crea un archivo de bloqueo de tipo world writable con propiedad root en el directorio /var/lock/apport de tipo world writable. Si el directorio apport/ no existe (esto no es raro ya que /var/lock es un tmpfs), creará el directorio, de lo contrario, simplemente continuará la ejecución usando el directorio existente. Esto permite un ataque de tipo symlink si un atacante creara un enlace simbólico en el directorio /var/lock/apport, cambiando la ubicación del archivo de bloqueo de apport. Este archivo podría ser utilizado para escalar privilegios, por ejemplo. Corregido en las versiones 2.20.1-0ubuntu2.23, 2.20.9-0ubuntu7.14, 2.20.11-0ubuntu8.8 y 2.20.11-0ubuntu22."
    }
  ],
  "lastModified": "2026-06-17T03:27:01.367",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:esm:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "815D70A8-47D3-459C-A32C-9FEACA0659D1"
            },
            {
              "criteria": "cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "7A5301BF-1402-4BE0-A0F8-69FBE79BC6D6"
            },
            {
              "criteria": "cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "23A7C53F-B80F-4E6A-AFA9-58EEA84BE11D"
            },
            {
              "criteria": "cpe:2.3:o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "A31C8344-3E02-4EB8-8BD8-4C84B7959624"
            }
          ],
          "operator": "OR"
        }
      ]
    },
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:apport_project:apport:-:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "47363193-B4DB-4654-BFAC-373426212337"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "security@ubuntu.com"
}