CVE-2011-5239 in CiviCRM
Summary
by MITRE
CiviCRM 4.0.5 and 4.1.1 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 • 02/23/2019
The vulnerability described in CVE-2011-5239 represents a critical SSL/TLS certificate validation flaw in CiviCRM versions 4.0.5 and 4.1.1. This issue stems from improper implementation of hostname verification during SSL certificate validation processes, creating a significant security risk for organizations relying on these web applications. The flaw specifically affects the X.509 certificate validation mechanism, which should enforce strict hostname matching against certificate subject fields to prevent unauthorized server impersonation.
This vulnerability falls under the category of weak cryptographic practices and certificate validation failures, aligning with CWE-295 which addresses improper certificate validation. The technical flaw occurs when the application fails to properly validate that the SSL certificate presented by the server matches the domain name being accessed. In normal operation, SSL/TLS connections should verify that the certificate's common name or subject alternative name fields contain a domain name that matches the target server's hostname. Without this verification, attackers can successfully perform man-in-the-middle attacks by presenting valid certificates for different domains, effectively allowing them to intercept and potentially modify communications between clients and servers.
The operational impact of this vulnerability is severe as it undermines the fundamental security assurances provided by SSL/TLS encryption. Attackers can exploit this weakness to impersonate legitimate CiviCRM servers, potentially gaining access to sensitive donor information, financial data, and personal records that organizations typically store in these systems. The vulnerability is particularly dangerous because it allows attackers to use any valid certificate, not just one specifically created for the target domain, making the attack surface significantly broader than typical certificate validation issues. This weakness creates a persistent threat vector that can be exploited across multiple network sessions and user interactions with the affected application.
Organizations affected by this vulnerability should prioritize immediate remediation through software updates to newer versions of CiviCRM that properly implement SSL certificate hostname verification. The mitigation strategy should include not only patching the application but also implementing comprehensive monitoring to detect potential exploitation attempts. Security teams should review existing SSL/TLS configurations and ensure that all certificate validation processes are properly enforced. Additionally, network-level protections such as certificate pinning and enhanced monitoring of SSL/TLS handshakes can provide additional defense in depth. This vulnerability demonstrates the critical importance of proper cryptographic implementation and highlights the need for regular security assessments of web applications, particularly those handling sensitive data. The issue also aligns with ATT&CK technique T1573 which covers secure communication protocols and emphasizes the importance of proper certificate validation in maintaining secure network communications.