CVE-2016-8629 in KeyCloak
Summary
by MITRE
Red Hat Keycloak before version 2.4.0 did not correctly check permissions when handling service account user deletion requests sent to the rest server. An attacker with service account authentication could use this flaw to bypass normal permissions and delete users in a separate realm.
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Analysis
by VulDB Data Team • 02/21/2023
The vulnerability identified as CVE-2016-8629 affects Red Hat Keycloak versions prior to 2.4.0, representing a critical authorization flaw within the identity and access management platform. This issue stems from inadequate permission validation mechanisms when processing service account user deletion requests through the REST server interface. The flaw creates a significant security gap that allows authenticated attackers to escalate their privileges beyond intended boundaries.
The technical implementation of this vulnerability resides in the insufficient input validation and access control checks within Keycloak's REST endpoint handling for service account operations. When a service account authenticates and sends a deletion request to the REST server, the system fails to properly verify whether the requesting entity has authorization to perform such operations across different realms. This misconfiguration enables attackers to manipulate the deletion process and target users in separate realms without proper authorization. The vulnerability manifests specifically during the service account user deletion workflow, where the permission checking logic does not adequately enforce realm boundaries.
From an operational perspective, this vulnerability presents a severe risk to organizations relying on Keycloak for identity management, as it allows attackers to perform unauthorized user deletion across realm boundaries. The impact extends beyond simple privilege escalation, potentially enabling attackers to disrupt user access, cause denial of service conditions, and compromise the integrity of the identity management system. The flaw particularly affects environments where multiple realms are configured, as the attacker can leverage a service account in one realm to delete users in another realm, bypassing normal access control policies.
The vulnerability aligns with CWE-285, which addresses improper authorization in software systems, and demonstrates characteristics consistent with privilege escalation attacks in identity management frameworks. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques where an attacker leverages existing credentials to gain broader access rights than initially intended. Organizations using Keycloak should consider this vulnerability as part of their broader identity and access management security posture, particularly in environments where realm isolation is critical for security segmentation.
Mitigation strategies for CVE-2016-8629 require immediate patching of Keycloak installations to version 2.4.0 or later, where the permission checking mechanisms have been properly implemented. Organizations should also review and strengthen their service account usage policies, ensuring that service accounts are granted minimal necessary privileges and that proper realm isolation controls are enforced. Network segmentation and monitoring of REST API access patterns can help detect anomalous deletion activities that might indicate exploitation attempts. Additionally, implementing comprehensive audit logging for user deletion operations across realms will provide better visibility into potential unauthorized access attempts and support forensic analysis if incidents occur.