CVE-2021-32803 Information

Description

The npm package ar\ (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.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H

Reference

https://www.npmjs.com/advisories/1771 https://github.com/npm/node-tar/security/advisories/GHSA-r628-mhmh-qjhw https://github.com/npm/node-tar/commit/9dbdeb6df8e9dbd96fa9e84341b9d74734be6c20 https://www.npmjs.com/package/tar https://www.oracle.com/security-alerts/cpuoct2021.html https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

REQUIRED

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

HIGH

Base Score

HIGH

Base Severity

8.1