gsd-2021-3493
Vulnerability from gsd
Modified
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


To clipboard 

{
  "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": {
        "ASSIGNER": "security@ubuntu.com",
        "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"
        }
      ],
      "data_format": "MITRE",
      "data_type": "CVE",
      "data_version": "4.0",
      "description": {
        "description_data": [
          {
            "lang": "eng",
            "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",
            "refsource": "MISC",
            "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",
            "refsource": "MISC",
            "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": [
              {
                "cpe23Uri": "cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:lts:*:*:*",
                "cpe_name": [],
                "versionEndExcluding": "20.04",
                "versionStartIncluding": "18.04.1",
                "vulnerable": true
              },
              {
                "cpe23Uri": "cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:lts:*:*:*",
                "cpe_name": [],
                "versionEndExcluding": "18.04",
                "vulnerable": true
              }
            ],
            "operator": "OR"
          },
          {
            "children": [],
            "cpe_match": [
              {
                "cpe23Uri": "cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:-:*:*:*",
                "cpe_name": [],
                "versionEndExcluding": "20.10",
                "vulnerable": true
              }
            ],
            "operator": "OR"
          }
        ]
      },
      "cve": {
        "CVE_data_meta": {
          "ASSIGNER": "security@ubuntu.com",
          "ID": "CVE-2021-3493"
        },
        "data_format": "MITRE",
        "data_type": "CVE",
        "data_version": "4.0",
        "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": [
                "Mailing List",
                "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",
              "refsource": "MISC",
              "tags": [
                "Mailing List",
                "Patch",
                "Third Party Advisory"
              ],
              "url": "https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52"
            },
            {
              "name": "https://ubuntu.com/security/notices/USN-4917-1",
              "refsource": "MISC",
              "tags": [
                "Vendor Advisory"
              ],
              "url": "https://ubuntu.com/security/notices/USN-4917-1"
            },
            {
              "name": "http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html",
              "refsource": "MISC",
              "tags": [
                "Exploit",
                "Third Party Advisory",
                "VDB Entry"
              ],
              "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"
              ],
              "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",
              "tags": [
                "Exploit",
                "Third Party Advisory",
                "VDB Entry"
              ],
              "url": "http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html"
            }
          ]
        }
      },
      "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"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.