CVE-2021-21355: Typo3/cms form Unrestricted File Upload Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-2r6j-862c-m2v2",
  "modified" : "2021-03-29T18:01:54Z",
  "published" : "2021-03-23T01:53:52Z",
  "aliases" : [ "CVE-2021-21355" ],
  "summary" : "Unrestricted File Upload in Form Framework",
  "details" : "\n### Problem\nDue to the lack of ensuring file extensions belong to configured allowed mime-types, attackers can upload arbitrary data with arbitrary file extensions - however, default _fileDenyPattern_ successfully blocked files like _.htaccess_ or _malicious.php_.\n\nTYPO3 Extbase extensions, which implement a file upload and do not implement a custom _TypeConverter_ to transform uploaded files into _FileReference_ domain model objects are affected by the vulnerability as well, since the _UploadedFileReferenceConverter_ of _ext:form_ handles the file upload and will accept files of any mime-type which are persisted to the default location.\n\nIn any way, uploaded files are placed in the default location _/fileadmin/user_upload/_, in most scenarios keeping the submitted filename - which allows attackers to directly reference files, or even correctly guess filenames used by other individuals, disclosing this information.\n\nNo authentication is required to exploit this vulnerability.\n\n### Solution\nUpdate to TYPO3 versions 8.7.40, 9.5.25, 10.4.14, 11.1.1 that fix the problem described.\n\nType converter _UploadedFileReferenceConverter_ is not registered globally anymore and just handles uploaded files within the scope of the Form Framework. Guessable storage location has changed from _/fileadmin/user_upload/form\\_\\<random-hash\\>/_ to _/fileadmin/form_uploads/<random-40-bit>_. Allowed mime-types must match expected file extensions (e.g. _application/pdf_ must be _.pdf_, and cannot be _.html_).\n\nExtbase extensions, who rely on the global availability of the _UploadedFileReferenceConverter_ must now implement a custom _TypeConverter_ to handle file uploads or explicitly implement the ext:form _UploadedFileReferenceConverter_ with appropriate setting for accepted mime-types.\n\n### Credits\nThanks to Sebastian Michaelsen, Marc Lindemann, Oliver Eglseder, Markus Volkmer, Jakob Kunzmann, Johannes Regner, Richie Lee who reported this issue, and to TYPO3 core & security team members Oliver Hader & Benni Mack, as well as TYPO3 contributor Ralf Zimmermann who fixed the issue.\n\n### References\n* [TYPO3-CORE-SA-2021-002](https://typo3.org/security/advisory/typo3-core-sa-2021-002)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L/E:F/RL:O/RC:C"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms-form"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "8.0.0"
      }, {
        "fixed" : "8.7.40"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 8.7.39"
    }
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms-form"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "9.0.0"
      }, {
        "fixed" : "9.5.25"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 9.5.24"
    }
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms-form"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "10.0.0"
      }, {
        "fixed" : "10.4.14"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 10.4.13"
    }
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms-form"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "11.0.0"
      }, {
        "fixed" : "11.1.1"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 11.1.0"
    }
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms-core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "10.0.0"
      }, {
        "fixed" : "10.4.14"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms-core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "11.0.0"
      }, {
        "fixed" : "11.1.1"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms-core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "9.0.0"
      }, {
        "fixed" : "9.5.25"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "10.0.0"
      }, {
        "fixed" : "10.4.14"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "11.0.0"
      }, {
        "fixed" : "11.1.1"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "typo3/cms"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "9.0.0"
      }, {
        "fixed" : "9.5.25"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/TYPO3/TYPO3.CMS/security/advisories/GHSA-2r6j-862c-m2v2"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-21355"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms-core/CVE-2021-21355.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms/CVE-2021-21355.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://packagist.org/packages/typo3/cms-form"
  }, {
    "type" : "WEB",
    "url" : "https://typo3.org/security/advisory/typo3-core-sa-2021-002"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-434", "CWE-552" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-03-23T01:41:38Z",
    "nvd_published_at" : "2021-03-23T02:15:00Z"
  }
}