When LDAP authentication is enabled in Apache Druid 0.17.0, callers of Druid APIs with a valid set of LDAP credentials can bypass the credentialsValidator.userSearch filter barrier that determines if a valid LDAP user is allowed to authenticate with Druid. They are still subject to role-based authorization checks, if configured. Callers of Druid APIs can also retrieve any LDAP attribute values of users that exist on the LDAP server, so long as that information is visible to the Druid server. This information disclosure does not require the caller itself to be a valid LDAP user.

Affected Products and Versions Apache Druid Affected Versions: 0.17.0 through 35.x (all versions prior to 36.0.0) Prerequisites: druid-basic-security extension enabled LDAP authenticator configured Underlying LDAP server permits anonymous bind

Vulnerability Description

An authentication bypass vulnerability exists in Apache Druid when using the druid-basic-security extension with LDAP authentication. If the underlying LDAP server is configured to allow anonymous binds, an attacker can bypass authentication by providing an existing username with an empty password. This allows unauthorized access to otherwise restricted Druid resources without valid credentials.

The vulnerability stems from improper validation of LDAP authentication responses when anonymous binds are permitted, effectively treating anonymous bind success as valid user authentication.

Impact

A remote, unauthenticated attacker can: Gain unauthorized access to the Apache Druid cluster Access sensitive data stored in Druid datasources Execute queries and potentially manipulate data Access administrative interfaces if the bypassed account has elevated privileges Completely compromise the confidentiality, integrity, and availability of the Druid deployment

Mitigation   Immediate Mitigation (No Druid Upgrade Required):                                                                                                                                                   Disable anonymous bind on your LDAP server. This prevents the vulnerability from being exploitable and is the recommended immediate action.

Resolution Upgrade Apache Druid to version 36.0.0 or later, which includes fixes to properly reject anonymous LDAP bind attempts.