CVE-2016-2217 in Socat
Summary
by MITRE
The OpenSSL address implementation in Socat 1.7.3.0 and 2.0.0-b8 does not use a prime number for the DH, which makes it easier for remote attackers to obtain the shared secret.
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Analysis
by VulDB Data Team • 08/07/2020
The vulnerability described in CVE-2016-2217 represents a critical weakness in the cryptographic implementation of the socat network utility when utilizing OpenSSL for secure communications. This flaw specifically affects versions 1.7.3.0 and 2.0.0-b8 of socat, which are widely used for creating bidirectional byte streams and network connections. The issue manifests in the Diffie-Hellman key exchange implementation where the software fails to utilize a prime number as required by proper cryptographic protocols, thereby weakening the security of encrypted communications. This vulnerability directly impacts the fundamental security guarantees that cryptographic protocols are designed to provide, making it particularly concerning for any system relying on socat for secure network communications.
The technical flaw stems from improper implementation of the Diffie-Hellman key exchange mechanism within socat's OpenSSL integration. In standard Diffie-Hellman key exchange, a large prime number serves as the modulus for the mathematical operations that generate the shared secret between communicating parties. When this prime number is not properly selected or implemented, it creates mathematical weaknesses that can be exploited by attackers using specialized tools and techniques. The vulnerability specifically relates to the generation or selection of the prime number used in the DH parameters, which should be a large, cryptographically secure prime to ensure the security of the key exchange process. This flaw falls under the category of cryptographic implementation weaknesses and can be classified as a CWE-326 weakness related to inadequate encryption strength.
The operational impact of this vulnerability extends beyond simple network security concerns as it fundamentally undermines the confidentiality and integrity of communications that rely on socat for secure connections. Remote attackers who can exploit this weakness gain significantly reduced difficulty in performing man-in-the-middle attacks or other cryptographic attacks against systems using vulnerable versions of socat. The vulnerability affects any system that uses socat with OpenSSL for secure network connections, potentially exposing sensitive data, authentication credentials, or private communications to unauthorized access. This weakness particularly impacts systems that rely on socat for VPN connections, secure shell tunnels, or any network service that requires robust key exchange mechanisms. The reduced security strength makes it easier for attackers to perform cryptanalysis and potentially recover the shared secret without requiring extensive computational resources or time.
Mitigation strategies for CVE-2016-2217 primarily involve updating to patched versions of socat where the Diffie-Hellman implementation properly uses secure prime numbers for key exchange operations. System administrators should immediately upgrade to versions of socat that have addressed this cryptographic weakness, typically those released after the vulnerability disclosure. Organizations should also consider implementing additional monitoring and detection mechanisms to identify any potential exploitation attempts against vulnerable systems. Security teams should review all systems that utilize socat for network communications and ensure proper patch management procedures are in place. The vulnerability demonstrates the importance of proper cryptographic implementation and highlights the need for thorough testing of cryptographic components, particularly those that interface with widely-used libraries like OpenSSL. This case underscores the critical nature of maintaining up-to-date cryptographic software and the potential consequences of failing to address known weaknesses in security-critical components. Organizations should also consider implementing network segmentation and additional security controls to reduce the potential impact of any successful exploitation attempts.