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CVE-2021-21411 Detail

Description

OAuth2-Proxy is an open source reverse proxy that provides authentication with Google, Github or other providers. The `--gitlab-group` flag for group-based authorization in the GitLab provider stopped working in the v7.0.0 release. Regardless of the flag settings, authorization wasn't restricted. Additionally, any authenticated users had whichever groups were set in `--gitlab-group` added to the new `X-Forwarded-Groups` header to the upstream application. While adding GitLab project based authorization support in #630, a bug was introduced where the user session's groups field was populated with the `--gitlab-group` config entries instead of pulling the individual user's group membership from the GitLab Userinfo endpoint. When the session groups where compared against the allowed groups for authorization, they matched improperly (since both lists were populated with the same data) so authorization was allowed. This impacts GitLab Provider users who relies on group membership for authorization restrictions. Any authenticated users in your GitLab environment can access your applications regardless of `--gitlab-group` membership restrictions. This is patched in v7.1.0. There is no workaround for the Group membership bug. But `--gitlab-project` can be set to use Project membership as the authorization checks instead of groups; it is not broken.


Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score matches with CNA score
CNA:  GitHub, Inc.
Base Score:  5.5 MEDIUM
Vector:  CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N


NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: The NVD and the CNA have provided the same score. When this occurs only the CNA information is displayed, but the Acceptance Level icon for the CNA is given a checkmark to signify NVD concurrence.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://docs.gitlab.com/ee/user/group/ Third Party Advisory 
https://github.com/oauth2-proxy/oauth2-proxy/commit/0279fa7dff1752f1710707dbd1ffac839de8bbfc Patch  Third Party Advisory 
https://github.com/oauth2-proxy/oauth2-proxy/releases/tag/v7.1.0 Release Notes  Third Party Advisory 
https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-652x-m2gr-hppm Third Party Advisory 
https://pkg.go.dev/github.com/oauth2-proxy/oauth2-proxy/v7 Product  Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-863 Incorrect Authorization Provider acceptance level GitHub, Inc.  

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Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2021-21411
NVD Published Date:
03/26/2021
NVD Last Modified:
04/06/2021
Source:
GitHub, Inc.