CVE-2012-5823 in Opensourceclassifieds
Summary
by MITRE
Open Source Classifieds 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 use of the PHP fsockopen function.
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Analysis
by VulDB Data Team • 03/16/2019
The vulnerability identified as CVE-2012-5823 affects the Open Source Classifieds platform and represents a critical SSL/TLS security flaw that undermines the fundamental integrity of secure communications. This weakness stems from improper certificate validation mechanisms within the application's SSL implementation, specifically when utilizing the PHP fsockopen function for establishing secure connections. The vulnerability creates a dangerous attack surface where malicious actors can execute successful man-in-the-middle attacks by presenting arbitrary valid certificates that appear legitimate to the client application. The root cause lies in the application's failure to properly validate SSL certificates against the expected server hostname, a critical security control that should prevent certificate forgery attacks.
The technical flaw manifests when the Open Source Classifieds application establishes SSL connections without performing proper hostname verification against the X.509 certificate presented by the server. This validation process should confirm that the certificate's Common Name field or Subject Alternative Name fields contain a domain name that matches the expected server hostname. The PHP fsockopen function, which is commonly used for creating socket connections, does not automatically enforce this validation, leaving the application vulnerable to attackers who can generate or obtain valid certificates for arbitrary domains. This oversight creates a scenario where attackers can intercept communications between clients and servers, potentially gaining access to sensitive information or manipulating data transfers.
The operational impact of this vulnerability extends beyond simple data interception, as it fundamentally compromises the trust model that secure communications rely upon. Attackers can exploit this weakness to impersonate legitimate servers and conduct various malicious activities including credential theft, session hijacking, and data manipulation. The vulnerability affects any communication channel that relies on SSL/TLS encryption within the Open Source Classifieds platform, potentially exposing user credentials, personal information, and classified advertisements to unauthorized access. Organizations using this platform face significant risks to their data security and user privacy, as the vulnerability can be exploited without requiring sophisticated attack techniques or significant resources.
Security professionals should recognize this vulnerability as a classic example of improper certificate validation, which aligns with CWE-295, which addresses issues related to validation of certificate with host name mismatch. The attack vector directly corresponds to techniques described in the MITRE ATT&CK framework under the T1573.002 sub-technique for "Encrypted Channel" and T1041 for "Exfiltration Over C2 Channel". Organizations should implement immediate mitigations including updating to patched versions of the Open Source Classifieds platform, implementing proper SSL certificate validation mechanisms, and ensuring that all applications perform strict hostname verification during SSL handshakes. Additionally, network monitoring solutions should be deployed to detect anomalous certificate behavior and unusual communication patterns that might indicate exploitation attempts. The vulnerability underscores the critical importance of proper SSL/TLS implementation and highlights the necessity of adhering to security best practices for certificate validation in all network communications.