CVE-2021-32804
Vulnérabilité élevée dans node-tar (npm)
Description
The npm package "tar" (aka node-tar) before versions 6.1.1, 5.0.6, 4.4.14, and 3.3.2 has a arbitrary File Creation/Overwrite vulnerability due to insufficient absolute path sanitization. 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`. This 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. This issue was addressed in releases 3.2.2, 4.4.14, 5.0.6 and 6.1.1. Users 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. See referenced GitHub Advisory for details. Be aware of CVE-2021-32803 which fixes a similar bug in later versions of tar.
Gravité et risque d'exploitation
CVE-2021-32804 obtient un score CVSS de 8.2/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 15.07 %, ce qui la place devant 96.7 % des CVE référencées.
Que faire ?
- Vérifiez si node-tar (versions >= 5.0.0, < 5.0.6, < 3.2.2, >= 6.0.0, < 6.1.1, >= 4.0.0, < 4.4.14) est présent sur votre parc.
- Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
- À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
- Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.
Références
- https://www.npmjs.com/package/tar
- https://github.com/npm/node-tar/security/advisories/GHSA-3jfq-g458-7qm9
- https://github.com/npm/node-tar/commit/1f036ca23f64a547bdd6c79c1a44bc62e8115da4
- https://www.npmjs.com/advisories/1770
- https://www.oracle.com/security-alerts/cpuoct2021.html
- https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
