Authentication bypass in Concourse

1) Improper Authentication

EUVDB-ID: #VU45747

Risk: Medium

CVSSv3.1: 4.9 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-5415

CWE-ID: CWE-287 - Improper Authentication

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass authentication process.

The vulnerability exists due to an error in when processing authentication requests. Installations which use the GitLab auth connector, are vulnerable to identity spoofing by way of configuring a GitLab account with the same full name as another user who is granted access to a Concourse team.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Pivotal Concourse: 6.3.0 - 6.4.0

External links

http://github.com/concourse/concourse/security/advisories/GHSA-627p-rr78-99rj
http://tanzu.vmware.com/security/cve-2020-5415

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.