CVE-2018-5447 in PCS-9611
Summary
by MITRE
An Improper Input Validation issue was discovered in Nari PCS-9611 relay. An improper input validation vulnerability has been identified that affects a service within the software that may allow a remote attacker to arbitrarily read/access system resources and affect the availability of the system.
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Analysis
by VulDB Data Team • 12/27/2019
The CVE-2018-5447 vulnerability represents a critical improper input validation flaw within the Nari PCS-9611 relay system, a sophisticated protective relaying device commonly deployed in power grid infrastructure. This vulnerability resides within the software service component that handles communication protocols and system operations, creating a significant security risk for critical infrastructure environments. The flaw stems from inadequate validation of input parameters received by the device's network services, which can be exploited by remote attackers without authentication. The vulnerability is classified under CWE-20 as improper input validation, specifically manifesting as a failure to properly sanitize or validate data received from external sources. This weakness allows attackers to manipulate input parameters in ways that bypass normal access controls and system safeguards.
The technical exploitation of this vulnerability enables remote attackers to perform arbitrary read operations against system resources, potentially accessing sensitive operational data, configuration files, or system memory contents. The impact extends beyond simple information disclosure to include potential availability disruption, as attackers can manipulate system resources in ways that may cause service degradation or complete system unavailability. The affected service within the Nari PCS-9611 likely processes network requests or communication protocols that do not adequately validate the format, length, or content of incoming data. This allows attackers to craft malicious inputs that can traverse normal system boundaries and access protected resources. The vulnerability's remote attack surface means that adversaries can exploit this flaw from outside the local network perimeter, making it particularly dangerous for industrial control systems and power grid infrastructure where physical security may be less stringent.
From an operational perspective, the implications of CVE-2018-5447 are severe for critical infrastructure operators who rely on Nari PCS-9611 devices for protective relaying functions. The ability to arbitrarily read system resources could expose operational parameters, security configurations, or control protocols that adversaries could leverage for more sophisticated attacks. The potential availability impact could disrupt power grid operations, affecting service delivery and potentially creating cascading failures in interconnected systems. This vulnerability aligns with ATT&CK tactics such as T1046 for network service scanning and T1005 for data from local system storage, demonstrating how initial reconnaissance can lead to system compromise. The attack vector represents a classic example of how insufficient input validation can create pathways for privilege escalation and system compromise, particularly in environments where devices operate with elevated privileges and handle critical infrastructure functions.
Organizations should implement immediate mitigations including network segmentation to isolate affected devices, deployment of intrusion detection systems to monitor for exploitation attempts, and application of vendor-supplied patches when available. The vulnerability highlights the importance of input validation in industrial control systems and emphasizes the need for comprehensive security testing of network services in critical infrastructure environments. Regular security assessments and vulnerability scanning should be conducted to identify similar input validation flaws in other industrial control system components. Additionally, implementing proper access controls, network monitoring, and regular security updates can significantly reduce the risk of exploitation. The incident underscores the critical need for security by design principles in industrial control systems, where traditional cybersecurity approaches may not be sufficient to address the unique risks posed by operational technology environments.