cve-2021-3493
Vulnerability from cvelistv5
Published
2021-04-17 04:20
Modified
2024-09-17 02:48
Severity ?
EPSS score ?
Summary
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.
References
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| ▼ | Ubuntu | linux kernel |
Version: 5.8 kernel < 5.8.0-50.56 Version: 5.4 kernel < 5.4.0-72.80 Version: 4.15 kernel < 4.15.0-142.146 Version: 4.4 kernel < 4.4.0-209.241 |
|
|
|||
CISA Known exploited vulnerability
Data from the Known Exploited Vulnerabilities Catalog
Date added: 2022-10-20
Due date: 2022-11-10
Required action: Apply updates per vendor instructions.
Used in ransomware: Unknown
Notes: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52; https://nvd.nist.gov/vuln/detail/CVE-2021-3493
{
"containers": {
"adp": [
{
"providerMetadata": {
"dateUpdated": "2024-08-03T16:53:17.827Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://ubuntu.com/security/notices/USN-4917-1"
},
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52"
},
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://www.openwall.com/lists/oss-security/2021/04/16/1"
},
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html"
},
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html"
},
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html"
}
],
"title": "CVE Program Container"
}
],
"cna": {
"affected": [
{
"product": "linux kernel",
"vendor": "Ubuntu",
"versions": [
{
"lessThan": "5.8.0-50.56",
"status": "affected",
"version": "5.8 kernel",
"versionType": "custom"
},
{
"lessThan": "5.4.0-72.80",
"status": "affected",
"version": "5.4 kernel",
"versionType": "custom"
},
{
"lessThan": "4.15.0-142.146",
"status": "affected",
"version": "4.15 kernel",
"versionType": "custom"
},
{
"lessThan": "4.4.0-209.241",
"status": "affected",
"version": "4.4 kernel",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"value": "An independent security researcher reporting to the SSD Secure Disclosure program"
}
],
"datePublic": "2021-04-15T00:00:00",
"descriptions": [
{
"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."
}
],
"metrics": [
{
"cvssV3_1": {
"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"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-270",
"description": "CWE-270: Privilege Context Switching Error",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2021-12-03T19:06:06",
"orgId": "cc1ad9ee-3454-478d-9317-d3e869d708bc",
"shortName": "canonical"
},
"references": [
{
"tags": [
"x_refsource_MISC"
],
"url": "https://ubuntu.com/security/notices/USN-4917-1"
},
{
"tags": [
"x_refsource_MISC"
],
"url": "https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52"
},
{
"tags": [
"x_refsource_MISC"
],
"url": "https://www.openwall.com/lists/oss-security/2021/04/16/1"
},
{
"tags": [
"x_refsource_MISC"
],
"url": "http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html"
},
{
"tags": [
"x_refsource_MISC"
],
"url": "http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html"
},
{
"tags": [
"x_refsource_MISC"
],
"url": "http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html"
}
],
"solutions": [
{
"lang": "en",
"value": "Apply https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52"
}
],
"source": {
"discovery": "EXTERNAL"
},
"workarounds": [
{
"lang": "en",
"value": "Disable unprivileged user namespaces."
}
],
"x_generator": {
"engine": "Vulnogram 0.0.9"
},
"x_legacyV4Record": {
"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": "en",
"value": "Apply https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52"
}
],
"source": {
"discovery": "EXTERNAL"
},
"work_around": [
{
"lang": "en",
"value": "Disable unprivileged user namespaces."
}
]
}
}
},
"cveMetadata": {
"assignerOrgId": "cc1ad9ee-3454-478d-9317-d3e869d708bc",
"assignerShortName": "canonical",
"cveId": "CVE-2021-3493",
"datePublished": "2021-04-17T04:20:16.706839Z",
"dateReserved": "2021-04-12T00:00:00",
"dateUpdated": "2024-09-17T02:48:12.994Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.1",
"meta": {
"cisa_known_exploited": {
"cveID": "CVE-2021-3493",
"cwes": "[\"CWE-862\"]",
"dateAdded": "2022-10-20",
"dueDate": "2022-11-10",
"knownRansomwareCampaignUse": "Unknown",
"notes": "https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52; https://nvd.nist.gov/vuln/detail/CVE-2021-3493",
"product": "Kernel",
"requiredAction": "Apply updates per vendor instructions.",
"shortDescription": "The overlayfs stacking file system in Linux kernel does not properly validate the application of file capabilities against user namespaces, which could lead to privilege escalation.",
"vendorProject": "Linux",
"vulnerabilityName": "Linux Kernel Privilege Escalation Vulnerability"
},
"nvd": "{\"cve\":{\"id\":\"CVE-2021-3493\",\"sourceIdentifier\":\"security@ubuntu.com\",\"published\":\"2021-04-17T05:15:14.630\",\"lastModified\":\"2024-11-21T06:21:40.433\",\"vulnStatus\":\"Modified\",\"cveTags\":[],\"descriptions\":[{\"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.\"},{\"lang\":\"es\",\"value\":\"La implementaci\u00f3n de overlayfs en el kernel de Linux no comprob\u00f3 apropiadamente con respecto a los espacios de nombre de los usuarios, la configuraci\u00f3n de las capacidades de los archivos en un sistema de archivos subyacente.\u0026#xa0;Debido a la combinaci\u00f3n de los espacios de nombre de usuarios no privilegiados junto con un parche incluido en el kernel de Ubuntu para permitir montajes de superposici\u00f3n no privilegiados, un atacante podr\u00eda usar esto para alcanzar privilegios elevados\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security@ubuntu.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H\",\"baseScore\":8.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":2.0,\"impactScore\":6.0},{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}],\"cvssMetricV2\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"2.0\",\"vectorString\":\"AV:L/AC:L/Au:N/C:C/I:C/A:C\",\"baseScore\":7.2,\"accessVector\":\"LOCAL\",\"accessComplexity\":\"LOW\",\"authentication\":\"NONE\",\"confidentialityImpact\":\"COMPLETE\",\"integrityImpact\":\"COMPLETE\",\"availabilityImpact\":\"COMPLETE\"},\"baseSeverity\":\"HIGH\",\"exploitabilityScore\":3.9,\"impactScore\":10.0,\"acInsufInfo\":false,\"obtainAllPrivilege\":false,\"obtainUserPrivilege\":false,\"obtainOtherPrivilege\":false,\"userInteractionRequired\":false}]},\"cisaExploitAdd\":\"2022-10-20\",\"cisaActionDue\":\"2022-11-10\",\"cisaRequiredAction\":\"Apply updates per vendor instructions.\",\"cisaVulnerabilityName\":\"Linux Kernel Privilege Escalation Vulnerability\",\"weaknesses\":[{\"source\":\"security@ubuntu.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-270\"}]},{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-863\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:lts:*:*:*\",\"versionEndExcluding\":\"18.04\",\"matchCriteriaId\":\"90A80DE7-3EFA-464C-9D31-C46521FFBFBF\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:lts:*:*:*\",\"versionStartIncluding\":\"18.04.1\",\"versionEndExcluding\":\"20.04\",\"matchCriteriaId\":\"2027773B-26DA-408E-B71D-40D05690D9EA\"}]}]},{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:-:*:*:*\",\"versionEndExcluding\":\"20.10\",\"matchCriteriaId\":\"ACAB2EE0-EC21-4669-840F-94F6C3028C64\"}]}]}],\"references\":[{\"url\":\"http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html\",\"source\":\"security@ubuntu.com\",\"tags\":[\"Exploit\",\"Third Party Advisory\",\"VDB Entry\"]},{\"url\":\"http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html\",\"source\":\"security@ubuntu.com\",\"tags\":[\"Third Party Advisory\",\"VDB Entry\"]},{\"url\":\"http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html\",\"source\":\"security@ubuntu.com\",\"tags\":[\"Exploit\",\"Third Party Advisory\",\"VDB Entry\"]},{\"url\":\"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52\",\"source\":\"security@ubuntu.com\",\"tags\":[\"Mailing List\",\"Patch\",\"Third Party Advisory\"]},{\"url\":\"https://ubuntu.com/security/notices/USN-4917-1\",\"source\":\"security@ubuntu.com\",\"tags\":[\"Vendor Advisory\"]},{\"url\":\"https://www.openwall.com/lists/oss-security/2021/04/16/1\",\"source\":\"security@ubuntu.com\",\"tags\":[\"Mailing List\",\"Third Party Advisory\"]},{\"url\":\"http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Exploit\",\"Third Party Advisory\",\"VDB Entry\"]},{\"url\":\"http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Third Party Advisory\",\"VDB Entry\"]},{\"url\":\"http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Exploit\",\"Third Party Advisory\",\"VDB Entry\"]},{\"url\":\"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Mailing List\",\"Patch\",\"Third Party Advisory\"]},{\"url\":\"https://ubuntu.com/security/notices/USN-4917-1\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Vendor Advisory\"]},{\"url\":\"https://www.openwall.com/lists/oss-security/2021/04/16/1\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Mailing List\",\"Third Party Advisory\"]}]}}"
}
}
Loading…
Loading…
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.