CVE-2006-4409 in Mac OS X
Summary
by MITRE
The Online Certificate Status Protocol (OCSP) service in the Security Framework in Apple Mac OS X 10.4 through 10.4.8 retrieve certificate revocation lists (CRL) when an HTTP proxy is in use, which could cause the system to accept certificates that have been revoked.
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Analysis
by VulDB Data Team • 06/15/2025
The vulnerability described in CVE-2006-4409 represents a critical flaw in Apple Mac OS X 10.4 through 10.4.8 systems that affects the Online Certificate Status Protocol implementation within the Security Framework. This issue specifically manifests when systems are configured to use an HTTP proxy server for network connectivity, creating a scenario where the operating system's certificate validation process becomes compromised. The fundamental problem lies in how the OCSP service handles certificate revocation checking when network traffic is routed through a proxy server, which directly impacts the system's ability to properly validate certificate status and reject revoked certificates.
The technical flaw stems from the improper handling of network proxy configurations during certificate validation processes. When an HTTP proxy is present in the system configuration, the OCSP service in affected Mac OS X versions fails to correctly process certificate revocation information, causing the system to potentially accept certificates that have been officially revoked. This behavior creates a significant security gap because the certificate validation mechanism that should prevent the use of compromised certificates becomes ineffective. The vulnerability is particularly concerning as it operates at the core security framework level, affecting how the operating system validates digital certificates used for secure communications, authentication, and data integrity protection. The flaw essentially allows attackers to bypass certificate validation controls that are essential for maintaining trust in digital security infrastructure.
The operational impact of this vulnerability extends beyond simple certificate acceptance issues and represents a serious threat to system security and trust. Systems running affected versions of Mac OS X become vulnerable to man-in-the-middle attacks, certificate forgery scenarios, and other security breaches where revoked certificates could be used to impersonate legitimate services or gain unauthorized access to protected resources. The vulnerability affects the entire certificate validation chain, potentially compromising secure web browsing, email communications, and other security-sensitive applications that rely on proper certificate validation. Organizations using these affected systems may experience security incidents where malicious actors exploit this weakness to establish fraudulent connections or access protected systems using compromised certificates that should have been rejected.
The security implications align with CWE-295 which addresses improper certificate validation and ATT&CK technique T1552.001 related to credentials from password storage components. This vulnerability creates opportunities for attackers to exploit the certificate validation process and potentially gain unauthorized access to systems or data. The flaw demonstrates a failure in secure communication protocols where the expected security controls are bypassed due to improper handling of proxy configurations. Organizations should implement immediate mitigations including updating to patched versions of Mac OS X, configuring proxy settings to avoid the vulnerable certificate validation path, or implementing additional security controls to monitor and detect potential exploitation attempts. The vulnerability also highlights the importance of proper certificate validation testing in networked environments where proxy servers are commonly used, emphasizing that security controls must function correctly regardless of network configuration complexities.
This vulnerability type represents a classic case of protocol implementation flaws that affect trust establishment in secure communications. The issue demonstrates how seemingly minor configuration handling differences can create significant security weaknesses in fundamental security infrastructure components. Organizations should consider this vulnerability as part of broader security assessments focusing on certificate validation, proxy configuration management, and secure communication protocol implementation. The affected versions of Mac OS X represent a specific window of vulnerability where the security framework failed to properly handle the interaction between certificate validation services and proxy network configurations. Proper security posture requires not only patching the specific vulnerability but also implementing comprehensive monitoring for potential exploitation attempts and ensuring that all certificate validation processes function correctly across different network configurations.