CVE-2018-4851 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 the device could cause a Denial-of-Service condition by sending certain packets to the device, causing potential reboots of the device. The core functionality of the device could be impacted. The time serving functionality recovers when time synchronization with GPS devices or other NTP servers are completed.
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Analysis
by VulDB Data Team • 04/03/2023
The vulnerability identified as CVE-2018-4851 affects SICLOCK TC100 and TC400 time synchronization devices, representing a critical denial-of-service weakness that undermines the reliability of industrial timekeeping infrastructure. These devices serve as time servers in critical systems where precise timing is essential for operations, making them attractive targets for adversaries seeking to disrupt time-sensitive processes. The vulnerability manifests through malformed packet transmission that can trigger device reboots, effectively removing the time synchronization service from operation and potentially causing cascading failures in dependent systems that rely on accurate time stamps for coordination and logging.
The technical flaw resides in the insufficient input validation mechanisms within the network protocol handling of these time synchronization devices. When the affected devices receive specially crafted packets, their processing routines fail to properly validate incoming data structures, leading to unexpected behavior that culminates in system reboot cycles. This vulnerability aligns with CWE-129, which addresses insufficient input validation, and demonstrates how network protocol implementation weaknesses can be exploited to cause system instability. The devices lack proper error handling and boundary checking mechanisms that would normally prevent malformed data from causing system-level failures.
The operational impact of this vulnerability extends beyond simple service disruption, as these time servers often operate in environments where time synchronization is critical for security operations, network coordination, and regulatory compliance. When a SICLOCK device reboots repeatedly, it creates gaps in time synchronization that can compromise the integrity of security logs, audit trails, and distributed system coordination. The recovery process requires manual intervention or successful completion of time synchronization with GPS or NTP sources, which may take considerable time and could result in significant operational downtime. This vulnerability particularly affects industrial control systems, network infrastructure, and security monitoring environments where these time servers are commonly deployed.
Organizations should implement immediate network segmentation to isolate these time synchronization devices from general network traffic, reducing exposure to potential attackers. Network access control lists should be configured to restrict communication to only trusted sources that require time synchronization services. Regular firmware updates should be applied as they become available from the vendor, and network monitoring should be enhanced to detect unusual reboot patterns or packet traffic that may indicate exploitation attempts. The vulnerability also highlights the importance of implementing redundant time synchronization sources and establishing automated monitoring for time server availability, as outlined in the MITRE ATT&CK framework's network intrusion detection and system recovery procedures. Additionally, security teams should develop incident response procedures specifically addressing time server failures to minimize operational impact during exploitation attempts.