#VU70623 Link following in Oras - CVE-2021-21272

Vulnerability identifier: #VU70623

Vulnerability risk: Medium

CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-21272

CWE-ID: CWE-59

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Oras

Vendor: Deislabs

Description

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

The vulnerability exists due to insecure hardlink following when extracting files from an archive. A remote attacker can trick the victim into downloading a gzipped tarballs that will be automatically extracted to the user-specified directory where the tarball can have symbolic links and hard links.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Oras: 0.4.0 - 0.8.1

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External links
https://github.com/deislabs/oras/commit/96cd90423303f1bb42bd043cb4c36085e6e91e8e
https://github.com/deislabs/oras/releases/tag/v0.9.0
https://pkg.go.dev/github.com/deislabs/oras/pkg/oras
https://github.com/deislabs/oras/security/advisories/GHSA-g5v4-5x39-vwhx

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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.