Vulnerability-Lookup

GHSA-9F46-5R25-5WFM

Vulnerability from github – Published: 2021-06-29 03:13 – Updated: 2021-09-21 14:55

Summary

Time-of-check Time-of-use (TOCTOU) Race Condition in league/flysystem

Details

Impact

The whitespace normalisation using in 1.x and 2.x removes any unicode whitespace. Under certain specific conditions this could potentially allow a malicious user to execute code remotely.

The conditions:

A user is allowed to supply the path or filename of an uploaded file.
The supplied path or filename is not checked against unicode chars.
The supplied pathname checked against an extension deny-list, not an allow-list.
The supplied path or filename contains a unicode whitespace char in the extension.
The uploaded file is stored in a directory that allows PHP code to be executed.

Given these conditions are met a user can upload and execute arbitrary code on the system under attack.

Patches

The unicode whitespace removal has been replaced with a rejection (exception).

The library has been patched in: - 1.x: https://github.com/thephpleague/flysystem/commit/f3ad69181b8afed2c9edf7be5a2918144ff4ea32 - 2.x: https://github.com/thephpleague/flysystem/commit/a3c694de9f7e844b76f9d1b61296ebf6e8d89d74

Workarounds

For 1.x users, upgrade to 1.1.4. For 2.x users, upgrade to 2.1.1.

Severity

9.8 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Show details on source website

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "league/flysystem"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.1.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "league/flysystem"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.0.0"
            },
            {
              "fixed": "2.1.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2021-32708"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-367"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2021-06-24T18:03:15Z",
    "nvd_published_at": "2021-06-24T17:15:00Z",
    "severity": "CRITICAL"
  },
  "details": "### Impact\n\nThe whitespace normalisation using in 1.x and 2.x removes any unicode whitespace. Under certain specific conditions this could potentially allow a malicious user to execute code remotely.\n\nThe conditions: \n\n- A user is allowed to supply the path or filename of an uploaded file.\n- The supplied path or filename is not checked against unicode chars.\n- The supplied pathname checked against an extension deny-list, not an allow-list.\n- The supplied path or filename contains a unicode whitespace char in the extension.\n- The uploaded file is stored in a directory that allows PHP code to be executed.\n\nGiven these conditions are met a user can upload and execute arbitrary code on the system under attack.\n\n### Patches\n\nThe unicode whitespace removal has been replaced with a rejection (exception).\n\nThe library has been patched in:\n- 1.x: https://github.com/thephpleague/flysystem/commit/f3ad69181b8afed2c9edf7be5a2918144ff4ea32\n- 2.x: https://github.com/thephpleague/flysystem/commit/a3c694de9f7e844b76f9d1b61296ebf6e8d89d74\n\n### Workarounds\n\nFor 1.x users, upgrade to 1.1.4. For 2.x users, upgrade to 2.1.1.\n",
  "id": "GHSA-9f46-5r25-5wfm",
  "modified": "2021-09-21T14:55:38Z",
  "published": "2021-06-29T03:13:28Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/thephpleague/flysystem/security/advisories/GHSA-9f46-5r25-5wfm"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-32708"
    },
    {
      "type": "WEB",
      "url": "https://github.com/thephpleague/flysystem/commit/a3c694de9f7e844b76f9d1b61296ebf6e8d89d74"
    },
    {
      "type": "WEB",
      "url": "https://github.com/thephpleague/flysystem/commit/f3ad69181b8afed2c9edf7be5a2918144ff4ea32"
    },
    {
      "type": "WEB",
      "url": "https://github.com/FriendsOfPHP/security-advisories/blob/master/league/flysystem/CVE-2021-32708.yaml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/thephpleague/flysystem"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NWPTENBYKI2IG47GI4DHAACLNRLTWUR5"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RNZSWK4GOMJOOHKLZEOE5AQSLC4DNCRZ"
    },
    {
      "type": "WEB",
      "url": "https://packagist.org/packages/league/flysystem"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Time-of-check Time-of-use (TOCTOU) Race Condition in league/flysystem"
}

CVE-2021-32708 (GCVE-0-2021-32708)

Vulnerability from cvelistv5 – Published: 2021-06-24 16:30 – Updated: 2024-08-03 23:25

Title

Time-of-check Time-of-use (TOCTOU) Race Condition in league/flysystem

Summary

Flysystem is an open source file storage library for PHP. The whitespace normalisation using in 1.x and 2.x removes any unicode whitespace. Under certain specific conditions this could potentially allow a malicious user to execute code remotely. The conditions are: A user is allowed to supply the path or filename of an uploaded file, the supplied path or filename is not checked against unicode chars, the supplied pathname checked against an extension deny-list, not an allow-list, the supplied path or filename contains a unicode whitespace char in the extension, the uploaded file is stored in a directory that allows PHP code to be executed. Given these conditions are met a user can upload and execute arbitrary code on the system under attack. The unicode whitespace removal has been replaced with a rejection (exception). For 1.x users, upgrade to 1.1.4. For 2.x users, upgrade to 2.1.1.

Severity

9.8 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE

CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition

Assigner

GitHub_M mitre root

References

6 references

URL	Tags
https://github.com/thephpleague/flysystem/securit…	x_refsource_CONFIRM
https://github.com/thephpleague/flysystem/commit/…	x_refsource_MISC
https://github.com/thephpleague/flysystem/commit/…	x_refsource_MISC
https://packagist.org/packages/league/flysystem	x_refsource_MISC
https://lists.fedoraproject.org/archives/list/pac…	vendor-advisoryx_refsource_FEDORA
https://lists.fedoraproject.org/archives/list/pac…	vendor-advisoryx_refsource_FEDORA

Impacted products

1 product

Vendor	Product	Version
thephpleague	flysystem	Affected: < 1.1.4 Affected: >= 2.0.0, < 2.1.1

Show details on NVD website

JSON

To clipboard

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      "metrics": [
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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