Doorkeeper Improper Authentication vulnerability

2023-06-1219:50:34

Google

osv.dev

doorkeeper

vulnerability

authorization

user consent

public clients

identity

impersonation

oauth

rfc 8252

CVSS3

6.5

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

LOW

Integrity Impact

LOW

Availability Impact

NONE

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

EPSS

0.002

Percentile

55.9%

JSON

OAuth RFC 8252 says https://www.rfc-editor.org/rfc/rfc8252#section-8.6

> the authorization server SHOULD NOT process authorization requests automatically without user consent or interaction, except when the identity of the client can be assured. This includes the case where the user has previously approved an authorization request for a given client id

But Doorkeeper automatically processes authorization requests without user consent for public clients that have been previously approved. Public clients are inherently vulnerable to impersonation, their identity cannot be assured.

Issue https://github.com/doorkeeper-gem/doorkeeper/issues/1589

Fix https://github.com/doorkeeper-gem/doorkeeper/pull/1646