CVE-2014-3568 in Xcode
Summary
by MITRE
OpenSSL before 0.9.8zc, 1.0.0 before 1.0.0o, and 1.0.1 before 1.0.1j does not properly enforce the no-ssl3 build option, which allows remote attackers to bypass intended access restrictions via an SSL 3.0 handshake, related to s23_clnt.c and s23_srvr.c.
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Analysis
by VulDB Data Team • 06/16/2022
This vulnerability resides in the OpenSSL cryptographic library implementation where the build configuration option no-ssl3 fails to properly prevent SSL 3.0 protocol support even when explicitly disabled during compilation. The flaw exists in the server and client handshake implementation files s23_clnt.c and s23_srvr.c which contain logic that allows SSL 3.0 connections to proceed despite the build-time restriction. This represents a critical security weakness that directly violates the principle of least privilege and configuration enforcement. The vulnerability is categorized under CWE-693 as a protection mechanism failure where the intended security controls are bypassed through improper implementation of protocol restrictions. From an operational perspective this allows attackers to establish SSL 3.0 connections even when the software was compiled with explicit SSL 3.0 disablement, creating a false sense of security for administrators who believe they have hardened their systems against the deprecated protocol.
The technical execution of this vulnerability occurs during the SSL handshake process where the SSL 3.0 protocol negotiation bypasses the compile-time restrictions that should have prevented such connections. Attackers can exploit this by initiating an SSL 3.0 handshake against a target system that was built with no-ssl3 enabled, effectively circumventing the intended security posture. This represents a direct violation of the secure configuration principle and demonstrates a failure in the build-time security controls. The vulnerability affects multiple OpenSSL versions including 0.9.8zc and earlier, 1.0.0o and earlier, and 1.0.1j and earlier releases, indicating a widespread issue across different version lines. The implementation flaw in s23_clnt.c and s23_srvr.c allows for protocol downgrade attacks where the system accepts SSL 3.0 connections despite explicit configuration to prohibit such protocols.
The operational impact of this vulnerability is severe as it undermines the fundamental security controls that organizations rely upon to prevent usage of deprecated and insecure protocols. SSL 3.0 is known to be vulnerable to the POODLE attack and other cryptographic weaknesses that make it unsuitable for production environments. This vulnerability allows threat actors to establish connections using the insecure SSL 3.0 protocol even when systems have been explicitly configured to disable it, effectively nullifying the security controls put in place. The vulnerability maps to attack techniques in the MITRE ATT&CK framework under T1071.004 for application layer protocol usage and T1566 for phishing with social engineering. Organizations that have deployed OpenSSL builds with no-ssl3 enabled may unknowingly be exposing themselves to attacks that leverage this bypass mechanism, creating a false positive security posture where systems appear hardened but remain vulnerable.
Mitigation strategies should focus on immediate patching of affected OpenSSL versions to the latest stable releases that contain the fix for this build-time configuration enforcement issue. System administrators should verify that their OpenSSL installations properly enforce the no-ssl3 build option and conduct audits to ensure that SSL 3.0 is truly disabled across all network services. The fix implemented in subsequent versions addresses the specific logic flaw in s23_clnt.c and s23_srvr.c that allowed SSL 3.0 handshakes to proceed despite build-time restrictions. Organizations should also implement network-level controls to prevent SSL 3.0 connections at the firewall or load balancer level as a defense-in-depth measure. Regular security assessments should verify that cryptographic library configurations are properly enforced and that no-ssl3 options are correctly implemented across all system components that utilize OpenSSL for secure communications. This vulnerability highlights the importance of proper build-time security controls and the need for comprehensive testing of security configuration enforcement mechanisms.