CVE-2012-1104 in phpCAS
Summary
by MITRE
A Security Bypass vulnerability exists in the phpCAS 1.2.2 library from the jasig project due to the way proxying of services are managed.
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Analysis
by VulDB Data Team • 12/06/2019
The vulnerability identified as CVE-2012-1104 represents a critical security bypass issue within the phpCAS 1.2.2 library, which is part of the Jasig project ecosystem. This library serves as a client implementation for Central Authentication Service (CAS) protocols, enabling single sign-on functionality across web applications. The flaw specifically manifests in how the library handles proxying of services, creating a pathway for unauthorized access that undermines the fundamental security guarantees of the CAS authentication mechanism. The vulnerability stems from inadequate validation of proxy service requests, allowing malicious actors to bypass normal authentication checks and gain access to protected resources.
The technical implementation flaw resides in the library's insufficient validation of proxy ticket assertions during service validation. When phpCAS processes proxy requests, it fails to properly verify the proxy chain integrity and the legitimacy of proxy service requests. This weakness allows attackers to manipulate the proxy ticket validation process, potentially enabling them to authenticate as any user or service within the CAS ecosystem. The vulnerability operates at the application layer and affects the authentication and authorization mechanisms that rely on phpCAS for secure service access. According to CWE classification, this maps to CWE-284: Improper Access Control, specifically manifesting as insufficient validation of proxy service requests within a single sign-on framework. The flaw enables attackers to exploit the trust relationship between services and the CAS server, creating a vector for privilege escalation and unauthorized data access.
The operational impact of CVE-2012-1104 extends beyond simple authentication bypass, potentially enabling attackers to compromise entire service ecosystems that depend on phpCAS for secure access control. Organizations utilizing vulnerable versions of phpCAS may experience unauthorized access to sensitive applications, data breaches, and potential lateral movement within their network infrastructure. The vulnerability affects any web application that relies on phpCAS for authentication, particularly those in academic and enterprise environments where CAS is commonly deployed. Attackers can leverage this weakness to impersonate legitimate users or services, potentially accessing confidential information, modifying system configurations, or conducting further reconnaissance. The impact is particularly severe in environments where phpCAS is used to secure multiple interconnected applications, as a single compromised instance can provide access to an entire service chain. This vulnerability aligns with ATT&CK technique T1078: Valid Accounts, as it allows adversaries to leverage legitimate authentication mechanisms to gain unauthorized access.
Mitigation strategies for CVE-2012-1104 require immediate action to upgrade to patched versions of the phpCAS library, as the vulnerability cannot be effectively addressed through configuration changes alone. Organizations should implement comprehensive vulnerability management processes to identify all systems utilizing vulnerable phpCAS versions and ensure prompt remediation. The recommended approach includes upgrading to phpCAS 1.2.3 or later, which contains the necessary fixes for proxy validation. Additionally, implementing network segmentation and monitoring for suspicious authentication patterns can help detect exploitation attempts. Security teams should conduct thorough audits of all applications using phpCAS to verify proper implementation and configuration. The fix addresses the core validation issue by strengthening proxy ticket verification and ensuring proper chain of trust validation. Organizations should also consider implementing additional security controls such as multi-factor authentication and regular security assessments to reduce the overall attack surface and improve resilience against similar vulnerabilities.