CVE-2017-2585 in KeyCloak
Summary
by MITRE
Red Hat Keycloak before version 2.5.1 has an implementation of HMAC verification for JWS tokens that uses a method that runs in non-constant time, potentially leaving the application vulnerable to timing attacks.
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Analysis
by VulDB Data Team • 02/21/2023
The vulnerability identified as CVE-2017-2585 affects Red Hat Keycloak versions prior to 2.5.1, specifically targeting the implementation of HMAC verification for JSON Web Signature (JWS) tokens. This flaw resides in the cryptographic validation process that Keycloak employs to authenticate and verify the integrity of security tokens used in authentication flows. The issue manifests in a critical security weakness that undermines the fundamental security guarantees expected from properly implemented cryptographic operations.
The technical flaw involves the use of a non-constant time algorithm for HMAC verification within the JWS token processing pipeline. In cryptographic contexts, constant-time algorithms are essential to prevent timing attacks that exploit variations in execution time to infer information about secret keys or internal states. When HMAC verification does not execute in constant time, an attacker can measure the time differences between successful and failed verification attempts to deduce information about the authentication token or the secret key used in the HMAC computation. This timing side-channel vulnerability directly violates established cryptographic best practices and security standards.
The operational impact of this vulnerability extends beyond simple authentication bypasses, as it creates a pathway for sophisticated attackers to perform credential harvesting attacks against Keycloak implementations. Attackers can leverage timing variations to gradually reconstruct secret keys or authentication tokens through repeated probing attempts, potentially compromising user sessions and access controls. The vulnerability affects the core authentication mechanism of Keycloak, which serves as a central identity and access management solution for numerous enterprise applications, making the potential impact significant across multiple organizational boundaries. This weakness particularly threatens systems where Keycloak manages sensitive authentication flows and where attackers have the ability to observe response times from the authentication service.
Organizations utilizing affected Keycloak versions should prioritize immediate remediation through the upgrade to version 2.5.1 or later, which incorporates proper constant-time HMAC verification implementations. Additional mitigations include implementing rate limiting and monitoring for unusual authentication patterns that might indicate timing attack attempts. The vulnerability aligns with CWE-327, which specifically addresses the use of weak cryptographic algorithms and improper implementation of cryptographic functions, and relates to ATT&CK technique T1212, which covers exploitation of cryptographic weakness. Security teams should also consider implementing network-level monitoring to detect potential timing attack patterns and ensure that all cryptographic implementations within their authentication infrastructure follow established security standards and undergo proper security review processes.