CVE-2014-2685 in Zend
Summary
by MITRE
The GenericConsumer class in the Consumer component in ZendOpenId before 2.0.2 and the Zend_OpenId_Consumer class in Zend Framework 1 before 1.12.4 violate the OpenID 2.0 protocol by ensuring only that at least one field is signed, which allows remote attackers to bypass authentication by leveraging an assertion from an OpenID provider.
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Analysis
by VulDB Data Team • 03/28/2022
The vulnerability identified as CVE-2014-2685 represents a critical security flaw in the OpenID authentication implementation within Zend Framework versions prior to 1.12.4 and ZendOpenId versions prior to 2.0.2. This issue stems from the GenericConsumer class and its handling of OpenID assertions, which fails to properly validate the complete signature chain required by the OpenID 2.0 specification. The flaw manifests when the system only verifies that at least one field within an OpenID assertion is signed rather than ensuring that all relevant fields undergo proper cryptographic validation, creating a significant bypass opportunity for malicious actors.
The technical implementation of this vulnerability exploits a fundamental weakness in the signature verification process by allowing attackers to manipulate OpenID assertions through carefully crafted modifications to unsigned fields. This occurs because the consumer component does not enforce the complete signature verification mandated by the OpenID 2.0 protocol, which requires that all fields in the assertion be cryptographically signed and validated. The vulnerability specifically targets the authentication flow where an OpenID provider sends an assertion that should be validated through cryptographic signatures, but the consumer accepts assertions that contain only partial signature coverage. This behavior violates the core principles of OpenID 2.0 protocol compliance and creates a trust relationship exploitation vector.
The operational impact of CVE-2014-2685 extends beyond simple authentication bypass to potentially enable session hijacking, unauthorized account access, and privilege escalation within applications relying on Zend Framework's OpenID implementation. Attackers can leverage this vulnerability to forge OpenID assertions that appear legitimate to the consumer component, effectively allowing them to authenticate as any user without proper credentials. The implications are particularly severe in web applications where OpenID is used for user authentication, as successful exploitation can lead to complete system compromise. This vulnerability directly aligns with CWE-347, which addresses the improper verification of cryptographic signatures, and represents a specific implementation flaw in the OpenID consumer validation process.
Mitigation strategies for CVE-2014-2685 require immediate patching of affected Zend Framework versions to 1.12.4 or later, and ZendOpenId to 2.0.2 or later, which contain proper signature verification implementations. Organizations should also implement additional security controls such as monitoring for unusual authentication patterns, implementing multi-factor authentication, and ensuring all OpenID assertions undergo complete cryptographic validation before acceptance. The fix addresses the root cause by enforcing proper signature verification that validates all fields in the OpenID assertion rather than accepting partial signature coverage, thereby restoring proper protocol compliance and authentication integrity. This vulnerability demonstrates the critical importance of cryptographic protocol adherence and highlights the potential consequences of insufficient signature validation in authentication systems.