CVE-2021-21411

Aliases:GHSA-652x-m2gr-hppmBIT-oauth2-proxy-2021-21411GO-2025-3832
Advisory lineage Upstream: 0 Downstream: 2
Modified
Published: 26 Mar 2021, 20:55
Last modified:03 Aug 2024, 18:09

Vulnerability Summary

Overall Risk (default)
low
22/100
CVSS Score
5.5 MEDIUM
v3.1 (cve.org)
EPSS Score
0.22% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

26 Mar 2021, 20:55
Published
Vulnerability first disclosed
03 Aug 2024, 18:09
Last Modified
Vulnerability information updated

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.

CVSS Metrics

  • v3.1•MEDIUM•Score: 5.5CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N
  • v2.0•MEDIUM•Score: 5.5AV:N/AC:L/Au:S/C:P/I:P/A:N

EPSS Trends

Current EPSS score: 0.22%• Percentile: 45%

Techniques & Countermeasures

  • CWE-863•Incorrect Authorization

    The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

Affected Systems

  • github.com/oauth2-proxy•oauth2-proxy

    all

  • github.com/oauth2-proxy/oauth2-proxy•v7

    < 7.1.0

  • oauth2_proxy_project•oauth2_proxy

    ≥ 7.0.0, < 7.1.0

  • oauth2-proxy•oauth2-proxy

    ≥ 7.0.0, < 7.1.0

References (8)