CVE-2021-32804: Tar Arbitrary File Creation/Overwrite Due To Vulnerability
HIGHCVE-2021-32804 is a HIGH (CVSS 8.2) arbitrary file creation/overwrite due to vulnerability (CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')) affecting Tar libraries in the npm ecosystem. The issue involves arbitrary file creation/overwrite due to insufficient absolute path sanitization. Remediation is available by upgrading affected packages to version 3.2.2, 4.4.14, 5.0.6, 6.1.1.
CVE-2021-32804 at a Glance
Security Impact
CVSS: 8.2
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N).
How to Fix CVE-2021-32804
To remediate this vulnerability, upgrade all affected Tar dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
npm install tar@3.2.2
npm install tar@4.4.14
npm install tar@5.0.6
npm install tar@6.1.1
Run the following command in your project directory to verify that all resolved dependencies use the patched release:
npm ls tar
How to Check if You Are Affected
To determine whether your Node.js application is affected by CVE-2021-32804, inspect your project dependencies using npm:
npm ls tar
Analyze the terminal output to locate any version of Tar in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.2.2), your application is affected.
Note: The npm ls tar command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'), where the product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. In Tar, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2021-32804 Affected Tar Versions
4 component(s)References
Frequently Asked Questions
What is CVE-2021-32804?
Which Tar versions are affected?
What version fixes CVE-2021-32804?
Is tar affected?
What is the CVSS score of CVE-2021-32804?
What CWE is associated with CVE-2021-32804?
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Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-3jfq-g458-7qm9",
"modified" : "2021-08-30T23:14:50Z",
"published" : "2021-08-03T19:06:36Z",
"aliases" : [ "CVE-2021-32804" ],
"summary" : "Arbitrary File Creation/Overwrite due to insufficient absolute path sanitization",
"details" : "### Impact\n\nArbitrary File Creation, Arbitrary File Overwrite, Arbitrary Code Execution\n\n`node-tar` aims to prevent extraction of absolute file paths by turning absolute paths into relative paths when the `preservePaths` flag is not set to `true`. This is achieved by stripping the absolute path root from any absolute file paths contained in a tar file. For example `/home/user/.bashrc` would turn into `home/user/.bashrc`. \n\nThis logic was insufficient when file paths contained repeated path roots such as `////home/user/.bashrc`. `node-tar` would only strip a single path root from such paths. When given an absolute file path with repeating path roots, the resulting path (e.g. `///home/user/.bashrc`) would still resolve to an absolute path, thus allowing arbitrary file creation and overwrite. \n\n### Patches\n\n3.2.2 || 4.4.14 || 5.0.6 || 6.1.1\n\nNOTE: an adjacent issue [CVE-2021-32803](https://github.com/npm/node-tar/security/advisories/GHSA-r628-mhmh-qjhw) affects this release level. Please ensure you update to the latest patch levels that address CVE-2021-32803 as well if this adjacent issue affects your `node-tar` use case.\n\n### Workarounds\n\nUsers may work around this vulnerability without upgrading by creating a custom `onentry` method which sanitizes the `entry.path` or a `filter` method which removes entries with absolute paths.\n\n```js\nconst path = require('path')\nconst tar = require('tar')\n\ntar.x({\n file: 'archive.tgz',\n // either add this function...\n onentry: (entry) => {\n if (path.isAbsolute(entry.path)) {\n entry.path = sanitizeAbsolutePathSomehow(entry.path)\n entry.absolute = path.resolve(entry.path)\n }\n },\n\n // or this one\n filter: (file, entry) => {\n if (path.isAbsolute(entry.path)) {\n return false\n } else {\n return true\n }\n }\n})\n```\n\nUsers are encouraged to upgrade to the latest patch versions, rather than attempt to sanitize tar input themselves.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "npm",
"name" : "tar"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "3.2.2"
} ]
} ]
}, {
"package" : {
"ecosystem" : "npm",
"name" : "tar"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "4.0.0"
}, {
"fixed" : "4.4.14"
} ]
} ]
}, {
"package" : {
"ecosystem" : "npm",
"name" : "tar"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "5.0.0"
}, {
"fixed" : "5.0.6"
} ]
} ]
}, {
"package" : {
"ecosystem" : "npm",
"name" : "tar"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "6.0.0"
}, {
"fixed" : "6.1.1"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/npm/node-tar/security/advisories/GHSA-3jfq-g458-7qm9"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-32804"
}, {
"type" : "WEB",
"url" : "https://github.com/npm/node-tar/commit/1f036ca23f64a547bdd6c79c1a44bc62e8115da4"
}, {
"type" : "WEB",
"url" : "https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/npm/node-tar"
}, {
"type" : "WEB",
"url" : "https://www.npmjs.com/advisories/1770"
}, {
"type" : "WEB",
"url" : "https://www.npmjs.com/package/tar"
}, {
"type" : "WEB",
"url" : "https://www.oracle.com/security-alerts/cpuoct2021.html"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-22" ],
"severity" : "HIGH",
"github_reviewed" : true,
"github_reviewed_at" : "2021-08-03T19:06:15Z",
"nvd_published_at" : "2021-08-03T19:15:00Z"
}
}