CVE-2012-5790 in Payments Standard
Summary
by MITRE
PayPal Payments Standard PHP Library 20120427 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, related to misinterpretation of a certain TRUE value.
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Analysis
by VulDB Data Team • 02/06/2018
The vulnerability identified as CVE-2012-5790 affects the PayPal Payments Standard PHP Library version 20120427, representing a critical SSL/TLS security flaw that undermines the integrity of secure communications. This issue stems from improper SSL certificate validation mechanisms within the library's implementation, creating a pathway for malicious actors to execute successful man-in-the-middle attacks against unsuspecting users. The flaw specifically resides in how the library processes SSL certificate verification, failing to properly validate that the server hostname matches either the Common Name field or subjectAltName fields within the X.509 certificate structure. This misinterpretation of certificate validation logic allows attackers to present any valid SSL certificate and successfully establish secure connections, effectively bypassing the fundamental security measures designed to protect against certificate forgery and impersonation attacks.
The technical implementation of this vulnerability demonstrates a failure in the SSL certificate validation process that aligns with CWE-295, which specifically addresses "Improper Certificate Validation." The flaw manifests when the library's SSL verification routine incorrectly handles a TRUE return value from certificate validation functions, leading to the acceptance of certificates that do not properly match the target server's hostname. This represents a classic case of insufficient hostname verification that enables attackers to exploit the trust relationship between clients and servers, particularly in payment processing contexts where data integrity and authenticity are paramount. The vulnerability operates at the application layer, specifically within the PHP library's SSL handling code, making it particularly dangerous as it affects the core security mechanisms of online payment transactions.
The operational impact of CVE-2012-5790 extends far beyond simple network security concerns, as it directly compromises the trust model underlying online payment processing systems. Attackers leveraging this vulnerability can intercept and manipulate payment transactions, potentially redirecting funds to malicious accounts or extracting sensitive financial information. The implications are particularly severe for e-commerce platforms and online service providers that rely on PayPal's payment processing capabilities, as the vulnerability undermines the fundamental security assumptions that users and merchants depend upon for safe financial transactions. This flaw creates an environment where attackers can establish fraudulent connections with payment servers, potentially leading to financial losses, data breaches, and compromised user trust. The vulnerability's impact is amplified by its ability to remain undetected, as the SSL connection appears legitimate to users and systems that do not perform additional validation checks beyond what the flawed library provides.
Mitigation strategies for this vulnerability require immediate attention and comprehensive implementation across affected systems. Organizations must prioritize updating to patched versions of the PayPal Payments Standard PHP Library, ensuring that all instances of the vulnerable code are replaced with secure implementations that properly validate SSL certificates against hostnames. System administrators should implement additional certificate validation measures, including manual verification of certificate chains and deployment of monitoring tools that can detect anomalous SSL connection patterns. The remediation process should also include comprehensive security testing of all payment processing components to identify potential additional vulnerabilities in related systems. According to ATT&CK framework category T1046, this vulnerability falls under network service scanning and exploitation techniques, making it essential for security teams to implement proper network segmentation and monitoring to detect and prevent unauthorized access attempts. Additionally, organizations should consider implementing certificate pinning mechanisms and enhanced logging of SSL connection activities to provide better visibility into potential exploitation attempts and maintain compliance with industry security standards.