CVE-2021-37712 Information

Description

The npm package ar\ (aka node-tar) before versions 4.4.18 5.0.10 and 6.1.9 has an arbitrary file creation/overwrite and arbitrary code execution vulnerability. 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 names containing unicode values that normalized to the same value. Additionally on Windows systems long path portions would resolve to the same file system entities as their 8.3 \short path\ counterparts. A specially crafted tar archive could thus include a directory with one form of the path followed by a symbolic link with a different string that resolves to the same file system entity followed by a file using the first form. By first creating a directory and then replacing that directory with a symlink that had a different apparent name that resolved to the same entry in the filesystem 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. These issues were addressed in releases 4.4.18 5.0.10 and 6.1.9. The v3 branch of node-tar has been deprecated and did not receive patches for these issues. If you are still using a v3 release we recommend you update to a more recent version of node-tar. If this is not possible a workaround is available in the referenced GHSA-qq89-hq3f-393p.

CVSS Vector

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

Reference

https://github.com/npm/node-tar/security/advisories/GHSA-qq89-hq3f-393p https://www.npmjs.com/package/tar https://www.oracle.com/security-alerts/cpuoct2021.html https://www.debian.org/security/2021/dsa-5008 https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

REQUIRED

Confidentiality Impact

CHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

8.6