CVE-2017-14028 in NPort 5110
Summary
by MITRE
A Resource Exhaustion issue was discovered in Moxa NPort 5110 Version 2.2, NPort 5110 Version 2.4, NPort 5110 Version 2.6, NPort 5110 Version 2.7, NPort 5130 Version 3.7 and prior, and NPort 5150 Version 3.7 and prior. An attacker may be able to exhaust memory resources by sending a large amount of TCP SYN packets.
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Analysis
by VulDB Data Team • 01/24/2021
The vulnerability identified as CVE-2017-14028 represents a critical resource exhaustion flaw affecting multiple Moxa NPort series network devices including the NPort 5110, 5130, and 5150 models across various firmware versions. This issue stems from inadequate handling of TCP SYN packets within the device's network stack implementation, creating a pathway for attackers to exploit the system's memory management mechanisms. The vulnerability specifically targets the TCP connection establishment process where the device fails to properly limit or manage the number of pending connection requests, allowing malicious actors to consume available memory resources through sustained SYN packet flooding attacks.
The technical implementation of this vulnerability manifests in the device's failure to enforce proper rate limiting and connection queue management during the TCP three-way handshake process. When the device receives an excessive number of TCP SYN packets without corresponding ACK responses, it maintains these incomplete connection states in memory, gradually consuming available RAM resources. This behavior aligns with CWE-400, which categorizes resource exhaustion vulnerabilities as those that allow attackers to deplete system resources through various means including memory, CPU, or network bandwidth consumption. The flaw essentially creates a denial of service condition where legitimate network traffic cannot be processed due to the device's inability to manage connection states effectively.
From an operational perspective, this vulnerability presents significant risk to industrial control systems and network infrastructure deployments where Moxa NPort devices are commonly utilized. The impact extends beyond simple service disruption as the resource exhaustion can lead to complete device unavailability, potentially affecting critical network connectivity for industrial automation systems, remote monitoring applications, or network segmentation controls. The vulnerability is particularly concerning in environments where network devices must maintain high availability and reliability, as attackers can easily exploit this weakness through automated tools to render network infrastructure non-functional. The attack vector requires minimal sophistication and can be executed from remote locations, making it an attractive target for both opportunistic and targeted attacks.
The exploitation of this vulnerability follows established patterns documented in the MITRE ATT&CK framework under the T1499 technique for network denial of service attacks. The attack lifecycle typically begins with reconnaissance to identify affected devices, followed by the deployment of SYN flood techniques that overwhelm the device's connection handling capabilities. Network administrators should consider implementing network segmentation, firewall rules to limit SYN packet rates, and monitoring solutions to detect unusual connection patterns. Additionally, regular firmware updates and patch management procedures are essential for maintaining device security posture, as Moxa has released fixes for this vulnerability in subsequent firmware versions. The incident highlights the importance of proper resource management in embedded network devices and underscores the need for robust input validation and rate limiting mechanisms in network infrastructure components. Organizations should also consider implementing intrusion detection systems to monitor for abnormal TCP connection patterns and establish incident response procedures for dealing with potential resource exhaustion attacks targeting industrial network equipment.