CVE-2016-4464 in CXF Fediz
Summary
by MITRE
The application plugins in Apache CXF Fediz 1.2.x before 1.2.3 and 1.3.x before 1.3.1 do not match SAML AudienceRestriction values against configured audience URIs, which might allow remote attackers to have bypass intended restrictions and have unspecified other impact via a crafted SAML token with a trusted signature.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 09/19/2022
The vulnerability identified as CVE-2016-4464 affects Apache CXF Fediz versions 1.2.x prior to 1.2.3 and 1.3.x prior to 1.3.1, representing a critical security flaw in the SAML authentication processing mechanism. This issue resides within the application plugins component of the Fediz framework, which serves as a SAML federation implementation for Apache CXF. The vulnerability stems from the improper validation of SAML AudienceRestriction elements during token processing, creating a significant security gap in the authentication flow that could be exploited by remote attackers to circumvent intended access controls.
The technical flaw manifests in the failure of the SAML processing logic to properly validate that the AudienceRestriction values in incoming SAML tokens match the configured audience URIs within the relying party configuration. This validation gap occurs during the token consumption phase where the system should verify that the SAML token is intended for the specific service or application that is processing it. When this check is omitted or improperly implemented, an attacker can craft a SAML token with a trusted signature but with modified AudienceRestriction values that point to different audiences than those configured in the target system. The vulnerability is categorized under CWE-284 Access Control Bypass, as it allows unauthorized access by bypassing the intended audience restrictions that should prevent tokens from being accepted by systems other than their intended recipients.
The operational impact of this vulnerability extends beyond simple authentication bypass, potentially enabling attackers to perform unauthorized access to protected resources across different applications or services that share the same SAML infrastructure. This flaw particularly affects scenarios where organizations rely on SAML-based federation for single sign-on and cross-domain authentication, as it undermines the fundamental principle that SAML tokens should only be accepted by their intended audience. Attackers could exploit this weakness to gain access to systems they should not be authorized to reach, potentially leading to data breaches, privilege escalation, or unauthorized data access. The unspecified other impacts suggest that the vulnerability might also enable additional attack vectors beyond simple access bypass, potentially including information disclosure or further compromise of the authentication infrastructure.
The vulnerability aligns with ATT&CK technique T1566.002 for phishing with social engineering and T1078.004 for valid accounts, as attackers could leverage this weakness to exploit trust relationships within federated authentication systems. Organizations using Apache CXF Fediz in production environments should immediately upgrade to versions 1.2.3 or 1.3.1 to remediate this vulnerability, as the flaw affects the core authentication validation logic and represents a significant weakening of the security posture for any system relying on SAML federation. The mitigation strategy involves not only applying the vendor-provided patches but also conducting thorough security assessments of existing SAML configurations to ensure that audience restrictions are properly enforced across all federated authentication endpoints.