GSD-2021-27851

Vulnerability from gsd - Updated: 2023-12-13 01:23
Details
A security vulnerability that can lead to local privilege escalation has been found in ’guix-daemon’. It affects multi-user setups in which ’guix-daemon’ runs locally. The attack consists in having an unprivileged user spawn a build process, for instance with `guix build`, that makes its build directory world-writable. The user then creates a hardlink to a root-owned file such as /etc/shadow in that build directory. If the user passed the --keep-failed option and the build eventually fails, the daemon changes ownership of the whole build tree, including the hardlink, to the user. At that point, the user has write access to the target file. Versions after and including v0.11.0-3298-g2608e40988, and versions prior to v1.2.0-75109-g94f0312546 are vulnerable.
Aliases
Aliases
CVE-2021-27851
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{
  "GSD": {
    "alias": "CVE-2021-27851",
    "description": "A security vulnerability that can lead to local privilege escalation has been found in \u2019guix-daemon\u2019. It affects multi-user setups in which \u2019guix-daemon\u2019 runs locally. The attack consists in having an unprivileged user spawn a build process, for instance with `guix build`, that makes its build directory world-writable. The user then creates a hardlink to a root-owned file such as /etc/shadow in that build directory. If the user passed the --keep-failed option and the build eventually fails, the daemon changes ownership of the whole build tree, including the hardlink, to the user. At that point, the user has write access to the target file. Versions after and including v0.11.0-3298-g2608e40988, and versions prior to v1.2.0-75109-g94f0312546 are vulnerable.",
    "id": "GSD-2021-27851",
    "references": [
      "https://www.suse.com/security/cve/CVE-2021-27851.html"
    ]
  },
  "gsd": {
    "metadata": {
      "exploitCode": "unknown",
      "remediation": "unknown",
      "reportConfidence": "confirmed",
      "type": "vulnerability"
    },
    "osvSchema": {
      "aliases": [
        "CVE-2021-27851"
      ],
      "details": "A security vulnerability that can lead to local privilege escalation has been found in \u2019guix-daemon\u2019. It affects multi-user setups in which \u2019guix-daemon\u2019 runs locally. The attack consists in having an unprivileged user spawn a build process, for instance with `guix build`, that makes its build directory world-writable. The user then creates a hardlink to a root-owned file such as /etc/shadow in that build directory. If the user passed the --keep-failed option and the build eventually fails, the daemon changes ownership of the whole build tree, including the hardlink, to the user. At that point, the user has write access to the target file. Versions after and including v0.11.0-3298-g2608e40988, and versions prior to v1.2.0-75109-g94f0312546 are vulnerable.",
      "id": "GSD-2021-27851",
      "modified": "2023-12-13T01:23:35.690603Z",
      "schema_version": "1.4.0"
    }
  },
  "namespaces": {
    "cve.org": {
      "CVE_data_meta": {
        "ASSIGNER": "cert@cert.org",
        "DATE_PUBLIC": "2021-03-18T00:00:00.000Z",
        "ID": "CVE-2021-27851",
        "STATE": "PUBLIC",
        "TITLE": "Local privilege escalation in GNU Guix via guix-daemon and \u0027--keep-failed\u0027"
      },
      "affects": {
        "vendor": {
          "vendor_data": [
            {
              "product": {
                "product_data": [
                  {
                    "product_name": "guix-daemon",
                    "version": {
                      "version_data": [
                        {
                          "version_affected": "\u003e=",
                          "version_value": "v0.11.0-3298-g2608e40988 "
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                        {
                          "version_affected": "\u003c",
                          "version_value": "v1.2.0-75109-g94f0312546"
                        }
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              },
              "vendor_name": "GNU Guix"
            }
          ]
        }
      },
      "credit": [
        {
          "lang": "eng",
          "value": "Nathan Nye of WhiteBeam Security"
        }
      ],
      "data_format": "MITRE",
      "data_type": "CVE",
      "data_version": "4.0",
      "description": {
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            "lang": "eng",
            "value": "A security vulnerability that can lead to local privilege escalation has been found in \u2019guix-daemon\u2019. It affects multi-user setups in which \u2019guix-daemon\u2019 runs locally. The attack consists in having an unprivileged user spawn a build process, for instance with `guix build`, that makes its build directory world-writable. The user then creates a hardlink to a root-owned file such as /etc/shadow in that build directory. If the user passed the --keep-failed option and the build eventually fails, the daemon changes ownership of the whole build tree, including the hardlink, to the user. At that point, the user has write access to the target file. Versions after and including v0.11.0-3298-g2608e40988, and versions prior to v1.2.0-75109-g94f0312546 are vulnerable."
          }
        ]
      },
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      },
      "problemtype": {
        "problemtype_data": [
          {
            "description": [
              {
                "lang": "eng",
                "value": "CWE-264 Permissions, Privileges, and Access Controls"
              }
            ]
          }
        ]
      },
      "references": {
        "reference_data": [
          {
            "name": "https://guix.gnu.org/en/blog/2021/risk-of-local-privilege-escalation-via-guix-daemon/",
            "refsource": "MISC",
            "url": "https://guix.gnu.org/en/blog/2021/risk-of-local-privilege-escalation-via-guix-daemon/"
          },
          {
            "name": "https://bugs.gnu.org/47229",
            "refsource": "MISC",
            "url": "https://bugs.gnu.org/47229"
          }
        ]
      },
      "source": {
        "discovery": "UNKNOWN"
      }
    },
    "nvd.nist.gov": {
      "configurations": {
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        "nodes": [
          {
            "children": [],
            "cpe_match": [
              {
                "cpe23Uri": "cpe:2.3:a:gnu:guix:*:*:*:*:*:*:*:*",
                "cpe_name": [],
                "versionEndExcluding": "1.2.0",
                "versionStartIncluding": "0.11.0",
                "vulnerable": true
              }
            ],
            "operator": "OR"
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      "cve": {
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          "ASSIGNER": "cert@cert.org",
          "ID": "CVE-2021-27851"
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        "description": {
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              "value": "A security vulnerability that can lead to local privilege escalation has been found in \u2019guix-daemon\u2019. It affects multi-user setups in which \u2019guix-daemon\u2019 runs locally. The attack consists in having an unprivileged user spawn a build process, for instance with `guix build`, that makes its build directory world-writable. The user then creates a hardlink to a root-owned file such as /etc/shadow in that build directory. If the user passed the --keep-failed option and the build eventually fails, the daemon changes ownership of the whole build tree, including the hardlink, to the user. At that point, the user has write access to the target file. Versions after and including v0.11.0-3298-g2608e40988, and versions prior to v1.2.0-75109-g94f0312546 are vulnerable."
            }
          ]
        },
        "problemtype": {
          "problemtype_data": [
            {
              "description": [
                {
                  "lang": "en",
                  "value": "CWE-59"
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        "references": {
          "reference_data": [
            {
              "name": "https://guix.gnu.org/en/blog/2021/risk-of-local-privilege-escalation-via-guix-daemon/",
              "refsource": "MISC",
              "tags": [
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                "Vendor Advisory"
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              "url": "https://guix.gnu.org/en/blog/2021/risk-of-local-privilege-escalation-via-guix-daemon/"
            },
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              "name": "https://bugs.gnu.org/47229",
              "refsource": "MISC",
              "tags": [
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                "Mailing List",
                "Patch",
                "Vendor Advisory"
              ],
              "url": "https://bugs.gnu.org/47229"
            }
          ]
        }
      },
      "impact": {
        "baseMetricV2": {
          "acInsufInfo": false,
          "cvssV2": {
            "accessComplexity": "LOW",
            "accessVector": "LOCAL",
            "authentication": "NONE",
            "availabilityImpact": "NONE",
            "baseScore": 2.1,
            "confidentialityImpact": "NONE",
            "integrityImpact": "PARTIAL",
            "vectorString": "AV:L/AC:L/Au:N/C:N/I:P/A:N",
            "version": "2.0"
          },
          "exploitabilityScore": 3.9,
          "impactScore": 2.9,
          "obtainAllPrivilege": false,
          "obtainOtherPrivilege": false,
          "obtainUserPrivilege": false,
          "severity": "LOW",
          "userInteractionRequired": false
        },
        "baseMetricV3": {
          "cvssV3": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "NONE",
            "baseScore": 5.5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N",
            "version": "3.1"
          },
          "exploitabilityScore": 1.8,
          "impactScore": 3.6
        }
      },
      "lastModifiedDate": "2022-07-29T16:34Z",
      "publishedDate": "2021-04-26T16:15Z"
    }
  }
}


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  • 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.
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  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
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  • 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.



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