CVE-2018-16737 in tinc
Summary
by MITRE
tinc before 1.0.30 has a broken authentication protocol, without even a partial mitigation.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 05/25/2023
The vulnerability identified as CVE-2018-16737 affects tinc versions prior to 1.0.30 and represents a critical flaw in the network tunneling software's authentication mechanism. This issue stems from a fundamental weakness in how the software handles cryptographic authentication between nodes in a virtual private network configuration, creating a pathway for unauthorized access and potential network compromise. The vulnerability exists in the core protocol implementation that governs how tinc nodes establish trust relationships with each other, making it particularly dangerous in environments where secure communication is paramount. The broken authentication protocol allows attackers to potentially impersonate legitimate nodes within the network, undermining the entire security model that tinc relies upon for maintaining secure connections between distributed systems.
The technical flaw manifests in the authentication process where tinc fails to properly validate cryptographic signatures and authentication tokens exchanged between nodes during the connection establishment phase. This weakness creates a scenario where an attacker can exploit the incomplete authentication mechanism to bypass security controls, potentially gaining access to sensitive network resources or performing man-in-the-middle attacks against legitimate communications. The vulnerability lacks any partial mitigation strategies, meaning that once exploited, the authentication system provides no protection against unauthorized access attempts. This absence of defensive measures makes the vulnerability particularly severe as it leaves network administrators with no alternative but to upgrade to patched versions to address the core issue. The flaw affects the cryptographic integrity of the entire tinc ecosystem, as the authentication protocol failure undermines the trust model that enables secure communication between nodes in distributed network configurations.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it can enable attackers to disrupt network services, intercept communications, or establish persistent access points within the network infrastructure. Organizations relying on tinc for secure communications between remote locations, distributed systems, or virtual private networks face significant risk when operating vulnerable versions. The vulnerability particularly affects environments where tinc is used for enterprise network connections, remote access solutions, or secure data transmission between geographically distributed systems. Attackers can exploit this weakness to gain unauthorized access to network resources, potentially leading to data breaches, service disruption, or further lateral movement within the compromised network infrastructure. The lack of any partial mitigation means that organizations must immediately address the vulnerability through version upgrades rather than implementing temporary workarounds.
Security mitigations for CVE-2018-16737 require immediate deployment of tinc version 1.0.30 or later, which includes corrected authentication protocols and cryptographic implementations. Network administrators should conduct comprehensive inventory checks to identify all systems running vulnerable versions of tinc and implement coordinated upgrade procedures to minimize service disruption. The vulnerability aligns with CWE-310, which addresses cryptographic issues in authentication mechanisms, and maps to ATT&CK technique T1078 for valid accounts and T1566 for credential harvesting through network attacks. Organizations should also implement network monitoring to detect potential exploitation attempts and consider additional security controls such as network segmentation, intrusion detection systems, and regular security audits to protect against unauthorized access. The fix implemented in version 1.0.30 addresses the core cryptographic weaknesses in the authentication protocol, ensuring proper signature validation and secure key exchange mechanisms that prevent the exploitation scenarios described in the vulnerability report.