Arbitrary File Creation/Overwrite via insufficient symlink protection due to directory cache poisoning (npm node-tar)

CVE-2021-32803
HIGH 8.2

At a glance

Source
NVD
EPSS
EPSS 7.80 % · percentile 95 ()
State
PUBLISHED
Published
Updated
Assigner
GitHub_M
NVD status
Modified

Description

The npm package "tar" (aka node-tar) before versions 6.1.2, 5.0.7, 4.4.15, and 3.2.3 has an arbitrary File Creation/Overwrite vulnerability via insufficient symlink protection. `node-tar` aims to guarantee that any file whose location would be modified by a symbolic link is not extracted. This is, in part, achieved by ensuring that extracted directories are not symlinks. Additionally, in order to prevent unnecessary `stat` calls to determine whether a given path is a directory, paths are cached when directories are created. This logic was insufficient when extracting tar files that contained both a directory and a symlink with the same name as the directory. This order of operations resulted in the directory being created and added to the `node-tar` directory cache. When a directory is present in the directory cache, subsequent calls to mkdir for that directory are skipped. However, this is also where `node-tar` checks for symlinks occur. By first creating a directory, and then replacing that directory with a symlink, it was thus possible to bypass `node-tar` symlink checks on directories, essentially allowing an untrusted tar file to symlink into an arbitrary location and subsequently extracting arbitrary files into that location, thus allowing arbitrary file creation and overwrite. This issue was addressed in releases 3.2.3, 4.4.15, 5.0.7 and 6.1.2.

Weaknesses (CWE)

  • CWE-22 — Improper Limitation of a Pathname to a Restricted Directory
  • CWE-59 — Improper Link Resolution Before File Access

References

Scores

VersionScoreVectorScored by
CVSS 3.1HIGH 8.2CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:NGitHub_M
CVSS 3.1HIGH 8.2CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:NNVD · security-advisories@github.com (Secondary)
CVSS 3.1HIGH 8.1CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:HNVD · nvd@nist.gov (Primary)
CVSS 2.0MEDIUM 5.8AV:N/AC:M/Au:N/C:N/I:P/A:PNVD · nvd@nist.gov (Primary)

Advisories

European references

CERT-FR advisories

Affected configurations (NVD CPE)

Affected products

ProductVersions
npm · node-taraffected < 3.2.3 ; affected >= 4.0.0, < 4.4.15 ; affected >= 5.0.0, < 5.0.7 ; affected >= 6.0.0, < 6.1.2

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD