GitHub Advisoryadvisory · PyPI
GHSA-384w-5v3f-q499 Base class whitelist configuration ignored in OAuthenticator
HIGH
Official page ↗
- Aliases
- CVE-2020-26250
- Ecosystem
- PyPI
- Packages
- oauthenticator
- Severity
- High
- CVSS vector
- CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
- Weaknesses
- CWE-863
- Reviewed
- 2020-12-01
Affected packages
• PyPI oauthenticator: >= 0.12.0, < 0.12.2 → fixed in 0.12.2
Description
Impact
__What goes wrong?__
The deprecated (in jupyterhub 1.2) configuration `Authenticator.whitelist`, which should be transparently mapped to `Authenticator.allowed_users` with a warning, is instead ignored by OAuthenticator classes, resulting in the same behavior as if this configuration has not been set. If this is the only mechanism of authorization restriction (i.e. no group or team restrictions in configuration) then all authenticated users will be allowed. Provider-based restrictions, including deprecated values such as `GitHubOAuthenticator.org_whitelist` are not affected.
__Who is impacted?__
All users of OAuthenticator 0.12.0 and 0.12.1 with JupyterHub 1.2 (JupyterHub Helm chart 0.10.0-0.10.5) who use the `admin.whitelist.users` configuration in the jupyterhub helm chart or the `c.Authenticator.whitelist` configuration directly. Users of other deprecated configuration, e.g. `c.GitHubOAuthenticator.team_whitelist` are not affected.
If you see a log line like this and expect a specific list of allowed usernames:
```
[I 2020-11-27 16:51:54.528 JupyterHub app:1717] Not using allowed_users. Any authenticated user will be allowed.
```
you are likely affected.
Patches
• Replacing deprecated `c.Authenticator.whitelist = ...` with `c.Authenticator.allowed_users = ...` avoids the issue.
• Update oauthenticator to 0.12.2
• Update jupyterhub helm chart to 0.10.6
If any users have been authorized during this time who should not have been, they must be deleted via the API or admin interface, per the documentation.
Workarounds
Replacing `c.Authenticator.whitelist = ...` with `c.Authenticator.allowed_users = ...` avoids the issue.
In the jupyterhub helm chart prior to 0.10.6, this can be done via `hub.extraConfig`:
```yaml
auth:
allowedUsers:
• user1
• user2
hub:
extraConfig:
allowedUsers: |
# set new field not exposed in helm chart < 0.10.6
set_config_if_not_none(c.Authenticator, "allowed_users", "auth.allowedUsers")
```
For more information
If you have any questions or comments about this advisory:
• Open a thread on the Jupyter forum
• Email us at [email protected]
Related
Alias · CVE (1)
- CVE-2020-26250 OAuthenticator is an OAuth login mechanism for JupyterHub. vulnerability
Weakness · CWE (1)
- CWE-863 Incorrect Authorization weakness
References
- https://github.com/jupyterhub/oauthenticator/security/advisories/GHSA-384w-5v3f-q499 web
- https://nvd.nist.gov/vuln/detail/CVE-2020-26250 advisory
- https://github.com/jupyterhub/oauthenticator/commit/a4aac191c16cf6281f3d346615aefa75702b02d7 web
- https://github.com/jupyterhub/oauthenticator package
- https://github.com/jupyterhub/oauthenticator/blob/master/docs/source/changelog.md#0122---2020-11-30 web
- https://github.com/pypa/advisory-database/tree/main/vulns/oauthenticator/PYSEC-2020-68.yaml web
- https://jupyterhub.readthedocs.io/en/1.2.2/getting-started/authenticators-users-basics.html#add-or-remove-users-from-the-hub web