Ecosyste.ms: Advisories

Security Advisories: MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLTM4NHctNXYzZi1xNDk5

Base class whitelist configuration ignored in OAuthenticator

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:

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]

Permalink: https://github.com/advisories/GHSA-384w-5v3f-q499
JSON: https://advisories.ecosyste.ms/api/v1/advisories/MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLTM4NHctNXYzZi1xNDk5
Source: GitHub Advisory Database
Origin: Unspecified
Severity: High
Classification: General
Published: over 3 years ago
Updated: over 1 year ago

CVSS Score: 6.3
CVSS vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N

Identifiers: GHSA-384w-5v3f-q499, CVE-2020-26250
References:

• https://github.com/jupyterhub/oauthenticator/security/advisories/GHSA-384w-5v3f-q499
• https://github.com/jupyterhub/oauthenticator/commit/a4aac191c16cf6281f3d346615aefa75702b02d7
• https://github.com/jupyterhub/oauthenticator/blob/master/docs/source/changelog.md#0122---2020-11-30
• https://jupyterhub.readthedocs.io/en/1.2.2/getting-started/authenticators-users-basics.html#add-or-remove-users-from-the-hub
• https://nvd.nist.gov/vuln/detail/CVE-2020-26250
• https://github.com/advisories/GHSA-384w-5v3f-q499

Repository: https://github.com/jupyterhub/oauthenticator
Blast Radius: 13.4

Affected Packages