CVE-2018-4856 in TC100
Summary
by MITRE
A vulnerability has been identified in SICLOCK TC100 (All versions) and SICLOCK TC400 (All versions). An attacker with administrative access to the device's management interface could lock out legitimate users. Manual interaction is required to restore the access of legitimate users.
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Analysis
by VulDB Data Team • 04/03/2023
The vulnerability identified in SICLOCK TC100 and TC400 devices represents a critical access control flaw that undermines the security posture of industrial time synchronization systems. These devices are designed to provide precise timing services in critical infrastructure environments where reliable network access is paramount. The vulnerability specifically targets the management interface authentication mechanisms, creating a scenario where an attacker with administrative privileges can deliberately restrict legitimate user access to the system. This issue affects all versions of both device models, indicating a fundamental design flaw rather than a specific software bug that might have been patched in later releases.
The technical nature of this vulnerability stems from insufficient access control validation within the device management interface. When an attacker with administrative credentials performs specific administrative actions, the system fails to properly maintain access permissions for other legitimate users. This flaw operates at the authentication and authorization level, creating a privilege escalation scenario where administrative privileges can be used to deny access to other users. The vulnerability requires manual intervention to resolve, which means that automated recovery mechanisms are not available, potentially leading to extended service disruption periods. The need for manual restoration suggests that the system does not maintain proper access control state information or does not provide adequate recovery procedures when access is intentionally restricted.
The operational impact of this vulnerability extends beyond simple access denial, as it creates a potential attack vector for malicious actors seeking to disrupt critical infrastructure operations. Industrial time synchronization systems like SICLOCK devices are often deployed in environments where precise timing is essential for coordination of critical processes, including power grid operations, telecommunications networks, and industrial control systems. When legitimate users are locked out of these systems, it can lead to cascading failures in time-sensitive operations that may require physical intervention to resolve. The requirement for manual restoration means that system administrators must be physically present at the device locations or have secure remote access to perform recovery procedures, which can be problematic in distributed or remote deployments. This vulnerability directly impacts the availability and integrity of time synchronization services that many critical infrastructure components depend upon.
Organizations should implement immediate mitigations including restricting administrative access to only trusted personnel, implementing robust access control procedures, and maintaining detailed documentation of administrative activities. The vulnerability aligns with CWE-285 which addresses improper authorization issues, and relates to ATT&CK technique T1078 which covers valid accounts for maintaining access. Network segmentation should be implemented to limit access to these devices to only necessary administrative personnel, while multi-factor authentication should be considered where available. Regular monitoring of administrative activities and access logs should be established to detect potential abuse of administrative privileges. Device firmware updates should be applied immediately when available, and organizations should develop incident response procedures specifically addressing this type of access control compromise. The vulnerability demonstrates the importance of maintaining proper access control state management and the need for robust recovery mechanisms in industrial control systems.