CVE-2023-27334 in edgeConnector Siemens
Summary
by MITRE • 05/03/2024
Softing edgeConnector Siemens ConditionRefresh Resource Exhaustion Denial-of-Service Vulnerability. This vulnerability allows remote attackers to create a denial-of-service condition on affected installations of Softing edgeConnector Siemens. Authentication is not required to exploit this vulnerability.
The specific flaw exists within the handling of OPC UA ConditionRefresh requests. By sending a large number of requests, an attacker can consume all available resources on the server. An attacker can leverage this vulnerability to create a denial-of-service condition on the system. Was ZDI-CAN-20498.
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Analysis
by VulDB Data Team • 08/13/2025
The CVE-2023-27334 vulnerability represents a critical resource exhaustion flaw within Softing edgeConnector Siemens software, specifically targeting the OPC UA ConditionRefresh functionality. This vulnerability operates as a remote denial-of-service condition that does not require authentication, making it particularly dangerous for industrial control systems and IoT deployments where such connectivity is essential. The affected system processes OPC UA requests through the ConditionRefresh mechanism, which serves as a core component for monitoring and managing industrial process conditions. The flaw stems from inadequate resource management and input validation within the software's OPC UA handler, allowing malicious actors to exploit the system's processing capabilities through crafted request sequences.
The technical implementation of this vulnerability involves the exploitation of the OPC UA protocol's ConditionRefresh operation, which is designed to synchronize condition states between client and server components in industrial automation environments. When an attacker sends an excessive number of ConditionRefresh requests, the edgeConnector Siemens application fails to properly throttle or limit incoming requests, leading to uncontrolled resource consumption. This resource exhaustion manifests through memory allocation failures, CPU saturation, and potential process termination, effectively rendering the industrial communication gateway unavailable to legitimate users. The vulnerability specifically targets the application layer of the OPC UA stack, where the server component fails to implement proper rate limiting or request queuing mechanisms to handle high-volume request patterns.
The operational impact of CVE-2023-27334 extends beyond simple service disruption, as it can severely compromise industrial control system availability and operational continuity. In manufacturing environments where edgeConnector Siemens serves as a critical communication bridge between field devices and enterprise systems, this vulnerability can lead to production halts, monitoring gaps, and potential safety issues. The lack of authentication requirements means that attackers can exploit this vulnerability from external networks without requiring insider knowledge or credentials, making it particularly attractive to threat actors targeting industrial infrastructure. The vulnerability aligns with CWE-400, which classifies resource exhaustion as a fundamental weakness in software design, and can be mapped to ATT&CK technique T1499.004 for network denial-of-service attacks. Organizations utilizing this software in critical infrastructure deployments face significant risk exposure, as the vulnerability can be exploited to create cascading failures that impact entire production lines or facility operations.
Mitigation strategies for CVE-2023-27334 should focus on implementing network-level protections and application-layer defenses to prevent exploitation. Network administrators should deploy firewalls and intrusion prevention systems to monitor and limit OPC UA traffic patterns, particularly targeting excessive ConditionRefresh request volumes. The software vendor has released patches addressing the resource management issues, and organizations should prioritize immediate deployment of these updates. Additionally, implementing request rate limiting mechanisms at the OPC UA server level can help prevent the exploitation of this vulnerability by limiting the number of ConditionRefresh operations per time period. Security teams should also consider network segmentation to isolate critical industrial control systems from general network access, reducing the attack surface for remote exploitation. The vulnerability demonstrates the importance of proper input validation and resource management in industrial communication protocols, aligning with security standards that emphasize robust error handling and resource allocation practices in critical infrastructure software development.