CVE-2012-5583 in phpCAS
Summary
by MITRE
phpCAS before 1.3.2 does not verify that the server hostname matches a domain name in the subject s Common Name (CN) or subjectAltName field of the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via an arbitrary valid certificate.
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Analysis
by VulDB Data Team • 04/24/2017
The vulnerability described in CVE-2012-5583 affects phpCAS versions prior to 1.3.2 and represents a critical flaw in SSL/TLS certificate validation mechanisms. This issue stems from insufficient hostname verification during SSL connections, specifically within the phpCAS library that is commonly used for implementing single sign-on authentication in web applications. The vulnerability allows attackers to perform man-in-the-middle attacks by presenting any valid SSL certificate, regardless of whether it matches the expected server hostname, effectively undermining the fundamental security guarantees provided by SSL/TLS protocols.
The technical root cause of this vulnerability lies in the improper implementation of X.509 certificate validation logic within the phpCAS library. When establishing secure connections, the system should verify that the server certificate's subject common name or subject alternative name fields contain a domain name that matches the expected hostname. However, phpCAS versions before 1.3.2 failed to perform this crucial validation step, allowing attackers to substitute their own valid certificates for the legitimate server certificates. This flaw directly violates the principles of certificate-based authentication and enables attackers to intercept and potentially manipulate communications between clients and servers without detection.
The operational impact of this vulnerability is severe and far-reaching within environments that rely on phpCAS for authentication services. Organizations using affected versions of phpCAS become vulnerable to various attack vectors including credential theft, session hijacking, and data interception. Attackers can exploit this weakness to impersonate legitimate servers and capture sensitive information such as login credentials, personal data, and confidential communications. The vulnerability is particularly dangerous in web applications where phpCAS is used for authentication, as it can compromise entire authentication systems and potentially lead to broader system compromises. This issue affects the integrity and confidentiality of all communications protected by the vulnerable phpCAS implementation.
Mitigation strategies for CVE-2012-5583 involve immediate upgrading to phpCAS version 1.3.2 or later, which contains the necessary certificate validation fixes. Organizations should also implement additional security measures such as monitoring for unauthorized certificate changes and conducting regular security assessments of authentication systems. The vulnerability aligns with CWE-295, which specifically addresses "Improper Certificate Validation," and maps to ATT&CK technique T1552.001 for "Unsecured Credentials" and T1046 for "Network Service Scanning." Security teams should also consider implementing certificate pinning mechanisms as an additional layer of protection, though this approach requires careful consideration of maintenance overhead and potential service disruption. Organizations should conduct comprehensive audits of their authentication infrastructure to identify all systems using vulnerable phpCAS versions and ensure proper certificate validation is enforced across all SSL/TLS connections.