CVE-2014-3510 in OpenSSL
Summary
by MITRE
The ssl3_send_client_key_exchange function in s3_clnt.c in OpenSSL 0.9.8 before 0.9.8zb, 1.0.0 before 1.0.0n, and 1.0.1 before 1.0.1i allows remote DTLS servers to cause a denial of service (NULL pointer dereference and client application crash) via a crafted handshake message in conjunction with a (1) anonymous DH or (2) anonymous ECDH ciphersuite.
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Analysis
by VulDB Data Team • 02/10/2022
The vulnerability described in CVE-2014-3510 represents a critical denial of service flaw within OpenSSL's DTLS implementation that affects multiple version branches including 0.9.8 through 0.9.8zb, 1.0.0 through 1.0.0n, and 1.0.1 through 1.0.1i. This issue specifically targets the ssl3_send_client_key_exchange function located in the s3_clnt.c file, which handles the client-side key exchange process during DTLS handshakes. The vulnerability arises when clients attempt to establish connections using anonymous Diffie-Hellman or anonymous Elliptic Curve Diffie-Hellman ciphersuites, which are inherently insecure but still supported for backward compatibility reasons.
The technical flaw manifests as a NULL pointer dereference condition that occurs when the ssl3_send_client_key_exchange function processes malformed handshake messages from malicious DTLS servers. During the key exchange phase, when using anonymous ciphersuites, the function fails to properly validate or handle specific message structures that contain crafted data. This improper validation leads to the dereferencing of a NULL pointer, causing the client application to crash abruptly and resulting in a denial of service condition that prevents legitimate users from establishing connections to affected services.
From an operational perspective, this vulnerability presents significant risk to systems that rely on DTLS for secure communications, particularly in environments where anonymous ciphersuites are enabled for legacy compatibility or specific use cases. The attack requires minimal privileges as it operates at the protocol level, making it accessible to remote attackers who can craft malicious handshake messages. The impact extends beyond simple service disruption to potentially compromise availability of critical infrastructure, especially in scenarios where DTLS is used for IoT device management, VoIP communications, or other time-sensitive applications where service continuity is paramount.
The vulnerability aligns with CWE-476, which specifically addresses NULL pointer dereference conditions, and demonstrates characteristics consistent with ATT&CK technique T1499.004 for network denial of service attacks. Organizations should prioritize immediate patching of affected OpenSSL versions, as the vulnerability affects widely deployed cryptographic libraries. Mitigation strategies include disabling anonymous DH and ECDH ciphersuites in server configurations, implementing proper input validation at the network level, and conducting thorough security audits of DTLS implementations. Additionally, system administrators should monitor for unusual connection patterns and implement intrusion detection systems to identify potential exploitation attempts, as the vulnerability can be leveraged to create sustained denial of service conditions against targeted services.