CVE-2021-21411
OAuth2-Proxy GitLab Group Membership Authorization Bypass Vulnerability
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.
INFO
Published Date :
March 26, 2021, 9:15 p.m.
Last Modified :
April 6, 2021, 12:42 p.m.
Source :
[email protected]
Remotely Exploitable :
Yes !
Impact Score :
2.7
Exploitability Score :
2.3
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2021-21411.
| URL | 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 |
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2021-21411 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-21411 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by [email protected]
May. 14, 2024
Action Type Old Value New Value -
Initial Analysis by [email protected]
Apr. 06, 2021
Action Type Old Value New Value Added CVSS V2 NIST (AV:N/AC:L/Au:S/C:P/I:P/A:N) Added CVSS V3.1 NIST AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N Changed Reference Type https://docs.gitlab.com/ee/user/group/ No Types Assigned https://docs.gitlab.com/ee/user/group/ Third Party Advisory Changed Reference Type https://github.com/oauth2-proxy/oauth2-proxy/commit/0279fa7dff1752f1710707dbd1ffac839de8bbfc No Types Assigned https://github.com/oauth2-proxy/oauth2-proxy/commit/0279fa7dff1752f1710707dbd1ffac839de8bbfc Patch, Third Party Advisory Changed Reference Type https://github.com/oauth2-proxy/oauth2-proxy/releases/tag/v7.1.0 No Types Assigned https://github.com/oauth2-proxy/oauth2-proxy/releases/tag/v7.1.0 Release Notes, Third Party Advisory Changed Reference Type https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-652x-m2gr-hppm No Types Assigned https://github.com/oauth2-proxy/oauth2-proxy/security/advisories/GHSA-652x-m2gr-hppm Third Party Advisory Changed Reference Type https://pkg.go.dev/github.com/oauth2-proxy/oauth2-proxy/v7 No Types Assigned https://pkg.go.dev/github.com/oauth2-proxy/oauth2-proxy/v7 Product, Third Party Advisory Added CPE Configuration OR *cpe:2.3:a:oauth2_proxy_project:oauth2_proxy:*:*:*:*:*:*:*:* versions from (including) 7.0.0 up to (excluding) 7.1.0
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-21411 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-21411
weaknesses.
Exploit Prediction
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.
0.11 }} 0.03%
score
0.43027
percentile