CVE-2021-32803 – tar

Package

Manager: npm
Name: tar
Vulnerable Version: >=3.0.0 <3.2.3 || >=4.0.0 <4.4.15 || >=5.0.0 <5.0.7 || >=6.0.0 <6.1.2

Severity

Level: High

CVSS v3.1: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

EPSS: 0.00242 pctl0.47405

Details

Arbitrary File Creation/Overwrite via insufficient symlink protection due to directory cache poisoning ### Impact Arbitrary File Creation, Arbitrary File Overwrite, Arbitrary Code Execution `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. ### Patches 3.2.3 || 4.4.15 || 5.0.7 || 6.1.2 ### Workarounds Users may work around this vulnerability without upgrading by creating a custom `filter` method which prevents the extraction of symbolic links. ```js const tar = require('tar') tar.x({ file: 'archive.tgz', filter: (file, entry) => { if (entry.type === 'SymbolicLink') { return false } else { return true } } }) ``` Users are encouraged to upgrade to the latest patch versions, rather than attempt to sanitize tar input themselves.

Metadata

Created: 2021-08-03T19:00:40Z
Modified: 2023-03-09T16:44:57Z
Source: https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/08/GHSA-r628-mhmh-qjhw/GHSA-r628-mhmh-qjhw.json
CWE IDs: ["CWE-22", "CWE-23", "CWE-59"]
Alternative ID: GHSA-r628-mhmh-qjhw
Finding: F063
Auto approve: 1