CVE-2018-4854 in TC100
Summary
by MITRE
A vulnerability has been identified in SICLOCK TC100 (All versions) and SICLOCK TC400 (All versions). An attacker with network access to port 69/udp could modify the administrative client stored on the device. If a legitimate user downloads and executes the modified client from the affected device, then he/she could obtain code execution on the client system.
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Analysis
by VulDB Data Team • 04/03/2023
The vulnerability identified as CVE-2018-4854 affects SICLOCK TC100 and TC400 time synchronization devices, representing a critical security flaw in industrial network infrastructure. These devices operate as time servers using the Trivial File Transfer Protocol (TFTP) on UDP port 69, which is commonly used for firmware updates and configuration file transfers in industrial environments. The vulnerability stems from insufficient authentication mechanisms and lack of file integrity verification during TFTP operations, creating an exploitable condition where network-based attackers can manipulate the administrative client stored on these devices.
The technical flaw manifests through the absence of cryptographic verification or authentication checks during TFTP transfers, allowing malicious actors to replace legitimate administrative client files with modified versions. This weakness directly maps to CWE-310, which addresses cryptographic weaknesses in data integrity verification processes. Attackers can leverage this vulnerability by intercepting network traffic or compromising network access to port 69/udp, where they can inject malicious payloads that overwrite the legitimate administrative client. The modified client contains malicious code that executes when a legitimate user downloads and runs the file, creating a persistent backdoor mechanism within the industrial control system environment.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it enables attackers to gain unauthorized code execution on client systems that interact with these time servers. This represents a significant threat to industrial control systems where time synchronization is critical for coordinated operations, potentially allowing attackers to disrupt time-sensitive processes or gain deeper access to connected industrial networks. The attack vector aligns with ATT&CK technique T1072, which describes application deployment through the use of remote services, and T1566, which covers phishing attacks through malicious file downloads. The vulnerability affects not only the immediate device but also the broader network ecosystem where these time servers operate, potentially enabling lateral movement attacks within industrial environments.
Mitigation strategies for CVE-2018-4854 should focus on network segmentation and access controls to prevent unauthorized access to UDP port 69, implementing firewall rules to restrict TFTP traffic to trusted networks only. Network administrators should also deploy intrusion detection systems capable of monitoring TFTP traffic for suspicious file modifications and implement cryptographic verification mechanisms for all file transfers. The recommended approach includes disabling TFTP services when not required, implementing secure file transfer protocols such as SFTP or FTPS, and conducting regular security audits of industrial network infrastructure. Organizations should also establish network monitoring procedures to detect unauthorized modifications to critical system files and ensure that all industrial devices maintain up-to-date firmware versions that address known vulnerabilities in their time synchronization protocols.