FKIE_CVE-2020-8833

Vulnerability from fkie_nvd - Published: 2020-04-22 22:15 - Updated: 2026-06-17 03:27
Severity
5.6 (Medium) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
4.7 (Medium) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
Summary
Time-of-check Time-of-use Race Condition vulnerability on crash report ownership change in Apport allows for a possible privilege escalation opportunity. If fs.protected_symlinks is disabled, this can be exploited between the os.open and os.chown calls when the Apport cron script clears out crash files of size 0. A symlink with the same name as the deleted file can then be created upon which chown will be called, changing the file owner to root. Fixed in versions 2.20.1-0ubuntu2.23, 2.20.9-0ubuntu7.14, 2.20.11-0ubuntu8.8 and 2.20.11-0ubuntu22.
References
security@ubuntu.comhttps://bugs.launchpad.net/ubuntu/+source/apport/+bug/1862933Exploit, Third Party Advisory
security@ubuntu.comhttps://usn.ubuntu.com/4315-1/Third Party Advisory
security@ubuntu.comhttps://usn.ubuntu.com/4315-2/Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://bugs.launchpad.net/ubuntu/+source/apport/+bug/1862933Exploit, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://usn.ubuntu.com/4315-1/Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108https://usn.ubuntu.com/4315-2/Third Party Advisory
Impacted products
Vendor Product Version
canonical ubuntu_linux 14.04
canonical ubuntu_linux 16.04
canonical ubuntu_linux 18.04
canonical ubuntu_linux 19.10
apport_project apport -
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "Apport",
          "vendor": "Canonical",
          "versions": [
            {
              "lessThan": "2.20.1-0ubuntu2.23",
              "status": "affected",
              "version": "2.20.1",
              "versionType": "custom"
            },
            {
              "lessThan": "2.20.9-0ubuntu7.14",
              "status": "affected",
              "version": "2.20.9",
              "versionType": "custom"
            },
            {
              "changes": [
                {
                  "at": "2.20.11-0ubuntu22",
                  "status": "unaffected"
                }
              ],
              "lessThan": "2.20.11-0ubuntu8.8",
              "status": "affected",
              "version": "2.20.11",
              "versionType": "custom"
            }
          ]
        }
      ],
      "source": "security@ubuntu.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
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              "matchCriteriaId": "815D70A8-47D3-459C-A32C-9FEACA0659D1",
              "vulnerable": true
            },
            {
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              "matchCriteriaId": "7A5301BF-1402-4BE0-A0F8-69FBE79BC6D6",
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              "matchCriteriaId": "A31C8344-3E02-4EB8-8BD8-4C84B7959624",
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            }
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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Time-of-check Time-of-use Race Condition vulnerability on crash report ownership change in Apport allows for a possible privilege escalation opportunity. If fs.protected_symlinks is disabled, this can be exploited between the os.open and os.chown calls when the Apport cron script clears out crash files of size 0. A symlink with the same name as the deleted file can then be created upon which chown will be called, changing the file owner to root. 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": "Una vulnerabilidad de Condici\u00f3n de Carrera de tipo Time-of-check Time-of-use en el cambio de propiedad del reporte de bloqueo en Apport, permite una posible oportunidad de escalada de privilegios. Si fs.protected_symlinks est\u00e1 deshabilitado, esto puede ser explotado entre las llamadas de os.open y os.chown cuando el script cron de Apport borra los archivos bloqueados de tama\u00f1o 0. Un enlace simb\u00f3lico con el mismo nombre que el archivo eliminado puede entonces ser creado a partir de que chown ser\u00eda llamado, cambiando el propietario del archivo a root. Corregido en las versiones 2.20.1-0ubuntu2.23, 2.20.9-0ubuntu7.14, 2.20.11-0ubuntu8.8 y 2.20.11-0ubuntu22."
    }
  ],
  "id": "CVE-2020-8833",
  "lastModified": "2026-06-17T03:27:01.667",
  "metrics": {
    "cvssMetricV2": [
      {
        "acInsufInfo": false,
        "baseSeverity": "LOW",
        "cvssData": {
          "accessComplexity": "MEDIUM",
          "accessVector": "LOCAL",
          "authentication": "NONE",
          "availabilityImpact": "NONE",
          "baseScore": 1.9,
          "confidentialityImpact": "PARTIAL",
          "integrityImpact": "NONE",
          "vectorString": "AV:L/AC:M/Au:N/C:P/I:N/A:N",
          "version": "2.0"
        },
        "exploitabilityScore": 3.4,
        "impactScore": 2.9,
        "obtainAllPrivilege": false,
        "obtainOtherPrivilege": false,
        "obtainUserPrivilege": false,
        "source": "nvd@nist.gov",
        "type": "Primary",
        "userInteractionRequired": false
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          "attackVector": "LOCAL",
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          "baseScore": 5.6,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N",
          "version": "3.1"
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        "impactScore": 4.0,
        "source": "security@ubuntu.com",
        "type": "Secondary"
      },
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        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "LOCAL",
          "availabilityImpact": "NONE",
          "baseScore": 4.7,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
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          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N",
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        "impactScore": 3.6,
        "source": "nvd@nist.gov",
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  },
  "published": "2020-04-22T22:15:12.577",
  "references": [
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      "tags": [
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    },
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    },
    {
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    {
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  "sourceIdentifier": "security@ubuntu.com",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
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          "value": "CWE-367"
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      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



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