#VU58205 Absolute Path Traversal in tar - CVE-2021-32804

Vulnerability identifier: #VU58205

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-32804

CWE-ID: CWE-36

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
tar
Web applications / JS libraries

Vendor: npm Inc.

Description

The vulnerability allows a remote attacker to overwrite arbitrary files on the system.

The vulnerability exists due to a logic issue 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.

Mitigation
Install update from vendor's website.

Vulnerable software versions

tar: 3.0.0 - 6.1.0

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External links
https://github.com/npm/node-tar/commit/1f036ca23f64a547bdd6c79c1a44bc62e8115da4
https://github.com/npm/node-tar/security/advisories/GHSA-3jfq-g458-7qm9

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.