CVE-2024-23656 in dex
Summary
by MITRE • 01/25/2024
Dex is an identity service that uses OpenID Connect to drive authentication for other apps. Dex 2.37.0 serves HTTPS with insecure TLS 1.0 and TLS 1.1. `cmd/dex/serve.go` line 425 seemingly sets TLS 1.2 as minimum version, but the whole `tlsConfig` is ignored after `TLS cert reloader` was introduced in v2.37.0. Configured cipher suites are not respected either. This issue is fixed in Dex 2.38.0.
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Analysis
by VulDB Data Team • 01/25/2024
The vulnerability identified as CVE-2024-23656 affects Dex version 2.37.0, an identity service implementing OpenID Connect authentication for applications. This represents a critical security flaw in the service's cryptographic configuration that undermines the integrity of secure communications. The issue stems from the introduction of a TLS certificate reloader feature in version 2.37.0, which inadvertently bypasses the intended security configurations. Despite the code at cmd/dex/serve.go line 425 appearing to set TLS 1.2 as the minimum version, the actual TLS configuration becomes ineffective due to this reloader mechanism. The vulnerability manifests through the use of insecure TLS 1.0 and TLS 1.1 protocols, which are deprecated and susceptible to various cryptographic attacks including POODLE and BEAST exploits. This weakness creates a pathway for attackers to intercept and potentially manipulate authentication flows between clients and the Dex service.
The technical flaw represents a configuration management error where the TLS security parameters are overridden by the certificate reloading mechanism. The issue extends beyond just protocol version selection as it also affects cipher suite enforcement, meaning that even if administrators configure specific secure cipher suites, these preferences are ignored due to the reloader implementation. This creates a situation where the service maintains an appearance of security through code comments and configuration parameters while actually operating with weakened cryptographic protections. The vulnerability is classified under CWE-310 as Cryptographic Vulnerability, specifically involving improper implementation of cryptographic protocols and the failure to properly enforce security configurations. The problem is particularly concerning because it affects the core authentication functionality of the service, potentially allowing attackers to perform man-in-the-middle attacks or capture authentication tokens.
The operational impact of this vulnerability is severe as it compromises the fundamental security of the identity service. Attackers exploiting this weakness can downgrade connections to insecure TLS versions, potentially enabling credential interception, session hijacking, or authentication bypass attempts. The vulnerability affects all applications relying on Dex for OpenID Connect authentication, creating widespread security implications across connected systems. Organizations using Dex 2.37.0 may experience unauthorized access to protected resources, data breaches, and potential compromise of user identities. This vulnerability directly maps to ATT&CK technique T1566.002 for credential access through phishing and T1071.004 for application layer protocol usage, as attackers can exploit the weakened TLS implementation to gain unauthorized access to authentication flows. The impact extends beyond immediate security breaches to potential long-term compromise of trust relationships within the authentication ecosystem.
The recommended mitigation involves immediate upgrade to Dex version 2.38.0 where the issue has been resolved. Organizations should also conduct thorough security audits of their Dex configurations to ensure no other insecure TLS settings persist. Security teams should monitor for any unauthorized access attempts or anomalies in authentication logs that might indicate exploitation of this vulnerability. Additional defensive measures include implementing network-level monitoring for TLS version mismatches and ensuring that all clients connecting to the Dex service are configured to use only secure TLS versions. The fix addresses both the TLS version enforcement and cipher suite respect issues, restoring proper cryptographic security controls. Organizations should also consider implementing certificate pinning and additional authentication layers as compensating controls while transitioning to the fixed version. This vulnerability highlights the importance of careful configuration management in security-critical services and the potential for seemingly benign feature additions to introduce significant security regressions.