Insecure hardlink processing in fstream npm module

1) UNIX hard link

EUVDB-ID: #VU20065

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-13173

CWE-ID: CWE-62 - UNIX Hard Link

Exploit availability: No

Description

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

The vulnerability exists due to insufficient validation of files within archives in fstream.DirWriter() function. A remote attacker can create a tarball containing a hardlink to a file that already exists in the system and overwrite arbitrary files on the system.

Successful exploitation of the vulnerability may allow remote code execution but requires the ability to pass specially crafted tarballs to the application.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

fstream: 1.0.0 - 1.0.11

External links

http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00010.html
http://github.com/npm/fstream/commit/6a77d2fa6e1462693cf8e46f930da96ec1b0bb22
http://www.npmjs.com/advisories/886

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.