CVE-2018-20835: Tar fs Improper Input Validation Vulnerability

HIGH
Advisory Identifier: GHSA-x2mc-8fgj-3wmr
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CVSS 7.5
CWE-20
Published
Advisory Summary

CVE-2018-20835 is a HIGH (CVSS 7.5) improper input validation vulnerability (CWE-20: Improper Input Validation) affecting Tar fs libraries in the npm ecosystem. The issue involves improper input validation in tar-fs. Remediation is available by upgrading affected packages to version 1.16.2.

CVE-2018-20835 at a Glance

CVE Identifier CVE-2018-20835
GHSA Identifier GHSA-x2mc-8fgj-3wmr
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-20: Improper Input Validation
Affected Product Tar fs
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2018-20835

To remediate this vulnerability, upgrade all affected Tar fs dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

tar-fs fixed: 1.16.2 
npm install tar-fs@1.16.2
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls tar-fs

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2018-20835, inspect your project dependencies using npm:

npm ls tar-fs

Analyze the terminal output to locate any version of Tar fs in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.16.2), your application is affected.

Note: The npm ls tar-fs 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-20: Improper Input Validation, where the product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. In Tar fs, 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

A vulnerability was found in tar-fs before 1.16.2. An Arbitrary File Overwrite issue exists when extracting a tarball containing a hardlink to a file that already exists on the system, in conjunction with a later plain file with the same name as the hardlink. This plain file content replaces the existing file content.

CVE-2018-20835 Affected Tar fs Versions

1 component(s)
Fixed Versions:
1.16.2
Product / Package Ecosystem Affected Versions Fixed Version
tar-fs
npm/tar-fs
npm
< 1.16.2
1.16.2

References

NVD — CVE-2018-20835 NVD
https://nvd.nist.gov/vuln/detail/CVE-2018-20835
Security Fix Commit FIX COMMIT
https://github.com/mafintosh/tar-fs/commit/06672828e6fa29ac8551b1b6f36c852a9a3c58a2
hackerone.com/reports/344595 WEB
https://hackerone.com/reports/344595
Tar fs Source Repository REPOSITORY
https://github.com/mafintosh/tar-fs/compare/d590fc7...a35ce2f

Frequently Asked Questions

What is CVE-2018-20835?
CVE-2018-20835 is a security vulnerability in Tar fs involving Improper Input Validation in tar-fs under CWE-20: Improper Input Validation.
Which Tar fs versions are affected?
Affected versions include releases prior to 1.16.2 across affected packages: tar-fs.
What version fixes CVE-2018-20835?
Upgrading to 1.16.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is tar-fs affected?
Yes, tar-fs is affected in releases prior to 1.16.2. Upgrade your dependency to 1.16.2 or later.
What is the CVSS score of CVE-2018-20835?
CVE-2018-20835 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.
What CWE is associated with CVE-2018-20835?
CVE-2018-20835 is classified under CWE-20: Improper Input Validation (The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.).
How can I check npm dependencies for CVE-2018-20835?
Run the dependency tree command: 'npm ls tar-fs'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-x2mc-8fgj-3wmr",
  "modified" : "2021-08-03T21:27:51Z",
  "published" : "2019-05-01T18:37:18Z",
  "aliases" : [ "CVE-2018-20835" ],
  "summary" : "Improper Input Validation in tar-fs",
  "details" : "A vulnerability was found in tar-fs before 1.16.2. An Arbitrary File Overwrite issue exists when extracting a tarball containing a hardlink to a file that already exists on the system, in conjunction with a later plain file with the same name as the hardlink. This plain file content replaces the existing file content.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "tar-fs"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.16.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2018-20835"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mafintosh/tar-fs/commit/06672828e6fa29ac8551b1b6f36c852a9a3c58a2"
  }, {
    "type" : "WEB",
    "url" : "https://hackerone.com/reports/344595"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mafintosh/tar-fs/compare/d590fc7...a35ce2f"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-20" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2019-05-01T18:25:25Z",
    "nvd_published_at" : "2019-04-30T19:29:00Z"
  }
}