CVE-2020-27295 in OPC UA Tunneller
Summary
by MITRE • 01/26/2021
The affected product has uncontrolled resource consumption issues, which may allow an attacker to cause a denial-of-service condition on the OPC UA Tunneller (versions prior to 6.3.0.8233).
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Analysis
by VulDB Data Team • 02/20/2021
The vulnerability identified as CVE-2020-27295 represents a critical resource consumption issue within OPC UA Tunneller implementations prior to version 6.3.0.8233. This flaw resides in the industrial communication protocol stack that facilitates secure data exchange between industrial automation systems and enterprise networks. The OPC UA Tunneller serves as a crucial bridge enabling remote access to industrial control systems while maintaining security boundaries. When exploited, this vulnerability creates a pathway for adversaries to manipulate system resources through carefully crafted requests that trigger excessive memory and CPU consumption patterns.
The technical exploitation of this vulnerability occurs through uncontrolled resource consumption mechanisms that allow attackers to submit malformed or excessive requests to the OPC UA Tunneller service. These requests trigger resource allocation behaviors that can lead to memory exhaustion, thread starvation, or CPU overload conditions. The flaw manifests when the system fails to properly validate or limit resource consumption during request processing, enabling attackers to consume resources at rates that exceed normal operational parameters. This behavior aligns with CWE-400, which categorizes uncontrolled resource consumption as a fundamental weakness in resource management within software systems. The vulnerability specifically targets the resource management logic within the tunneller's request handling components, where input validation mechanisms prove insufficient to prevent resource exhaustion attacks.
From an operational perspective, the impact of this vulnerability extends beyond simple service disruption to potentially compromise entire industrial control environments. The denial-of-service condition can render critical infrastructure communication channels unavailable, affecting production processes, monitoring systems, and operational continuity. In industrial settings where OPC UA Tunneller services maintain connectivity to critical manufacturing equipment, this vulnerability can result in significant financial losses and operational downtime. The attack surface is particularly concerning in environments where industrial systems operate with minimal redundancy, as the service disruption can cascade to affect downstream processes. Security professionals should consider this vulnerability in the context of the MITRE ATT&CK framework, specifically under the T1499.004 technique for network denial of service attacks, which targets availability through resource exhaustion.
Mitigation strategies for CVE-2020-27295 primarily focus on upgrading to the patched version 6.3.0.8233 or later, which incorporates enhanced resource validation and consumption limits within the OPC UA Tunneller implementation. Organizations should also implement network segmentation and access controls to limit exposure of vulnerable systems to untrusted networks. Additional protective measures include implementing rate limiting mechanisms, monitoring resource consumption patterns for anomalous behavior, and establishing automated alerting systems for unusual resource utilization. The vulnerability demonstrates the importance of proper resource management in industrial protocols and highlights the need for comprehensive security testing of communication components in operational technology environments. Security teams should conduct thorough vulnerability assessments of their industrial control system components and ensure regular patch management processes are in place to address similar resource consumption issues in other industrial communication protocols.