CVE-2023-0657 in Keycloak
Summary
by MITRE • 11/17/2024
A flaw was found in Keycloak. This issue occurs due to improperly enforcing token types when validating signatures locally. This could allow an authenticated attacker to exchange a logout token for an access token and possibly gain access to data outside of enforced permissions.
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Analysis
by VulDB Data Team • 11/17/2024
The vulnerability identified as CVE-2023-0657 represents a critical authorization flaw within the Keycloak identity and access management platform that undermines the integrity of token validation processes. This issue specifically targets the local signature validation mechanism where the system fails to properly enforce token type constraints during authentication checks. The flaw exists in the way Keycloak processes and validates tokens, creating a potential pathway for malicious actors to manipulate authentication flows and escalate their privileges within the system. The vulnerability impacts the fundamental security model of Keycloak by allowing unauthorized access to resources that should be restricted based on proper token validation. This represents a significant weakness in the platform's ability to maintain secure authentication boundaries and enforce access controls effectively.
The technical root cause of this vulnerability stems from insufficient type checking during local token signature validation operations within Keycloak's authentication framework. When an attacker successfully authenticates to the system, they can potentially exploit the flawed validation logic to substitute one token type for another, specifically exchanging a logout token for an access token. This misconfiguration allows the system to accept unauthorized token types without proper verification of their intended purpose or scope. The flaw operates at the core validation layer where cryptographic signatures are verified, yet the system fails to ensure that the token type matches the expected validation context. This type confusion vulnerability creates a scenario where the authentication system cannot properly distinguish between different token purposes, leading to potential privilege escalation and unauthorized data access. The vulnerability aligns with CWE-224, which addresses weaknesses in token validation and authorization enforcement mechanisms, and demonstrates a failure in proper input validation and type integrity checking.
The operational impact of CVE-2023-0657 extends beyond simple unauthorized access to potentially enable comprehensive data breaches within Keycloak-protected environments. An authenticated attacker who successfully exploits this vulnerability can gain access to resources and information that should be restricted to specific user roles or permissions. This could result in exposure of sensitive data, unauthorized modification of system configurations, or complete compromise of the authentication infrastructure. The vulnerability particularly affects organizations that rely heavily on Keycloak for managing user identities and access controls, as it undermines the trust model that the platform is designed to provide. Attackers could leverage this flaw to move laterally within systems, access restricted administrative functions, or obtain credentials for other services that depend on Keycloak for authentication. The impact is amplified in environments where Keycloak serves as a central authentication point for multiple applications and services, as a single exploitation could compromise the entire authentication ecosystem.
Organizations utilizing Keycloak must implement immediate mitigations to address this vulnerability, beginning with applying the latest security patches provided by Red Hat or the Keycloak development team. The recommended approach includes enabling additional token validation checks and strengthening the local signature verification process to ensure proper token type enforcement. Security teams should conduct thorough audits of their Keycloak configurations to identify potential exploitation vectors and implement network segmentation to limit the impact of successful attacks. Organizations should also consider implementing monitoring solutions that can detect unusual token exchange patterns or unauthorized access attempts that may indicate exploitation of this vulnerability. The mitigation strategy should include regular security assessments of authentication flows, enhanced logging of token validation events, and review of access control policies to ensure that proper authorization boundaries remain intact. This vulnerability demonstrates the critical importance of maintaining robust token validation mechanisms and aligns with ATT&CK technique T1566, which addresses credential access through manipulation of authentication systems, emphasizing the need for comprehensive security controls around identity management platforms.