GSD-2021-3493

Vulnerability from gsd - Updated: 2023-12-13 01:23
Details
The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges.
Aliases
Aliases
CVE-2021-3493
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{
  "GSD": {
    "alias": "CVE-2021-3493",
    "description": "The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges.",
    "id": "GSD-2021-3493",
    "references": [
      "https://www.suse.com/security/cve/CVE-2021-3493.html",
      "https://ubuntu.com/security/CVE-2021-3493",
      "https://packetstormsecurity.com/files/cve/CVE-2021-3493"
    ]
  },
  "gsd": {
    "metadata": {
      "exploitCode": "unknown",
      "remediation": "unknown",
      "reportConfidence": "confirmed",
      "type": "vulnerability"
    },
    "osvSchema": {
      "aliases": [
        "CVE-2021-3493"
      ],
      "details": "The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges.",
      "id": "GSD-2021-3493",
      "modified": "2023-12-13T01:23:34.785270Z",
      "schema_version": "1.4.0"
    }
  },
  "namespaces": {
    "cve.org": {
      "CVE_data_meta": {
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        "DATE_PUBLIC": "2021-04-15T00:00:00.000Z",
        "ID": "CVE-2021-3493",
        "STATE": "PUBLIC"
      },
      "affects": {
        "vendor": {
          "vendor_data": [
            {
              "product": {
                "product_data": [
                  {
                    "product_name": "linux kernel",
                    "version": {
                      "version_data": [
                        {
                          "version_affected": "\u003c",
                          "version_name": "5.8 kernel",
                          "version_value": "5.8.0-50.56 "
                        },
                        {
                          "version_affected": "\u003c",
                          "version_name": "5.4 kernel",
                          "version_value": " 5.4.0-72.80 "
                        },
                        {
                          "version_affected": "\u003c",
                          "version_name": "4.15 kernel",
                          "version_value": "4.15.0-142.146 "
                        },
                        {
                          "version_affected": "\u003c",
                          "version_name": "4.4 kernel",
                          "version_value": " 4.4.0-209.241"
                        }
                      ]
                    }
                  }
                ]
              },
              "vendor_name": "Ubuntu"
            }
          ]
        }
      },
      "credit": [
        {
          "lang": "eng",
          "value": "An independent security researcher reporting to the SSD Secure Disclosure program"
        }
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      "data_format": "MITRE",
      "data_type": "CVE",
      "data_version": "4.0",
      "description": {
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            "value": "The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges."
          }
        ]
      },
      "generator": {
        "engine": "Vulnogram 0.0.9"
      },
      "impact": {
        "cvss": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
          "version": "3.1"
        }
      },
      "problemtype": {
        "problemtype_data": [
          {
            "description": [
              {
                "lang": "eng",
                "value": "CWE-270: Privilege Context Switching Error"
              }
            ]
          }
        ]
      },
      "references": {
        "reference_data": [
          {
            "name": "https://ubuntu.com/security/notices/USN-4917-1",
            "refsource": "MISC",
            "url": "https://ubuntu.com/security/notices/USN-4917-1"
          },
          {
            "name": "https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52",
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            "url": "https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52"
          },
          {
            "name": "https://www.openwall.com/lists/oss-security/2021/04/16/1",
            "refsource": "MISC",
            "url": "https://www.openwall.com/lists/oss-security/2021/04/16/1"
          },
          {
            "name": "http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html",
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            "url": "http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html"
          },
          {
            "name": "http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html",
            "refsource": "MISC",
            "url": "http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html"
          },
          {
            "name": "http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html",
            "refsource": "MISC",
            "url": "http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html"
          }
        ]
      },
      "solution": [
        {
          "lang": "eng",
          "value": "Apply https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "work_around": [
        {
          "lang": "eng",
          "value": "Disable unprivileged user namespaces."
        }
      ]
    },
    "nvd.nist.gov": {
      "configurations": {
        "CVE_data_version": "4.0",
        "nodes": [
          {
            "children": [],
            "cpe_match": [
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                "cpe23Uri": "cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:lts:*:*:*",
                "cpe_name": [],
                "versionEndExcluding": "20.04",
                "versionStartIncluding": "18.04.1",
                "vulnerable": true
              },
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            "operator": "OR"
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            "cpe_match": [
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                "versionEndExcluding": "20.10",
                "vulnerable": true
              }
            ],
            "operator": "OR"
          }
        ]
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      "cve": {
        "CVE_data_meta": {
          "ASSIGNER": "security@ubuntu.com",
          "ID": "CVE-2021-3493"
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        "data_format": "MITRE",
        "data_type": "CVE",
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        "description": {
          "description_data": [
            {
              "lang": "en",
              "value": "The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges."
            }
          ]
        },
        "problemtype": {
          "problemtype_data": [
            {
              "description": [
                {
                  "lang": "en",
                  "value": "CWE-863"
                }
              ]
            }
          ]
        },
        "references": {
          "reference_data": [
            {
              "name": "https://www.openwall.com/lists/oss-security/2021/04/16/1",
              "refsource": "MISC",
              "tags": [
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                "Third Party Advisory"
              ],
              "url": "https://www.openwall.com/lists/oss-security/2021/04/16/1"
            },
            {
              "name": "https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52",
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            },
            {
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              "url": "http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html"
            },
            {
              "name": "http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html",
              "refsource": "MISC",
              "tags": [
                "Third Party Advisory",
                "VDB Entry"
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            }
          ]
        }
      },
      "impact": {
        "baseMetricV2": {
          "acInsufInfo": false,
          "cvssV2": {
            "accessComplexity": "LOW",
            "accessVector": "LOCAL",
            "authentication": "NONE",
            "availabilityImpact": "COMPLETE",
            "baseScore": 7.2,
            "confidentialityImpact": "COMPLETE",
            "integrityImpact": "COMPLETE",
            "vectorString": "AV:L/AC:L/Au:N/C:C/I:C/A:C",
            "version": "2.0"
          },
          "exploitabilityScore": 3.9,
          "impactScore": 10.0,
          "obtainAllPrivilege": false,
          "obtainOtherPrivilege": false,
          "obtainUserPrivilege": false,
          "severity": "HIGH",
          "userInteractionRequired": false
        },
        "baseMetricV3": {
          "cvssV3": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "HIGH",
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "exploitabilityScore": 1.8,
          "impactScore": 5.9
        }
      },
      "lastModifiedDate": "2023-07-07T19:10Z",
      "publishedDate": "2021-04-17T05:15Z"
    }
  }
}


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