CVE-2020-1694 in KeyCloak
Summary
by MITRE
A flaw was found in all versions of Keycloak before 10.0.0, where the NodeJS adapter did not support the verify-token-audience. This flaw results in some users having access to sensitive information outside of their permissions.
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Analysis
by VulDB Data Team • 09/17/2020
The vulnerability identified as CVE-2020-1694 represents a critical authentication and authorization flaw within the Keycloak identity and access management platform. This issue affects all versions of Keycloak prior to 10.0.0 and specifically targets the NodeJS adapter component that facilitates integration between Node.js applications and Keycloak's authentication services. The flaw stems from insufficient token validation mechanisms that fail to properly verify the audience claim within authentication tokens, creating a significant security gap that undermines the integrity of access control policies.
The technical root cause of this vulnerability lies in the NodeJS adapter's failure to implement proper token audience verification as specified in the OAuth 2.0 and OpenID Connect standards. When Keycloak generates authentication tokens, these tokens contain an audience field that specifies which applications or services are authorized to accept and process them. The missing verify-token-audience functionality means that the NodeJS adapter accepts tokens regardless of whether they were intended for the specific application, effectively bypassing the intended scope and permissions. This behavior directly correlates to CWE-287 which addresses improper authentication mechanisms and represents a fundamental breakdown in the principle of least privilege enforcement.
The operational impact of this vulnerability is severe and multifaceted, as it allows malicious actors or compromised users to potentially access sensitive information and resources beyond their designated permissions. An attacker who gains access to a valid authentication token could exploit this weakness to impersonate other users or gain unauthorized access to protected resources within applications that rely on Keycloak for authentication. This creates a potential escalation path where users with limited access could obtain elevated privileges or access data that should be restricted to specific user groups or roles. The vulnerability particularly affects applications that depend on the NodeJS adapter for authentication and authorization, making it a critical concern for organizations with extensive Node.js deployments using Keycloak.
Organizations affected by this vulnerability should immediately upgrade to Keycloak version 10.0.0 or later where the verify-token-audience functionality has been properly implemented. The mitigation strategy should also include comprehensive auditing of existing authentication tokens and access controls to identify any potential unauthorized access that may have occurred. Security teams should also implement additional monitoring and logging mechanisms to detect suspicious authentication patterns and token usage that could indicate exploitation attempts. The remediation process should include thorough testing of the updated NodeJS adapter to ensure that legitimate applications continue to function properly while the security gap is closed. This vulnerability highlights the importance of proper token validation in distributed authentication systems and aligns with ATT&CK technique T1566 which covers credential harvesting through various authentication bypass methods.