CVE-2017-14435 in EDR-810
Summary
by MITRE
An exploitable denial of service vulnerability exists in the web server functionality of Moxa EDR-810 V4.1 build 17030317. A specially crafted HTTP URI can cause a null pointer dereference resulting in denial of service. An attacker can send a GET request to "/MOXA\_CFG.ini" without a cookie header to trigger this vulnerability.
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Analysis
by VulDB Data Team • 03/13/2023
The vulnerability identified as CVE-2017-14435 represents a critical denial of service weakness within the Moxa EDR-810 industrial network device firmware version 4.1 build 17030317. This flaw resides in the web server component that handles HTTP requests, specifically targeting the configuration file access mechanism. The device operates in industrial environments where continuous network availability is paramount, making this vulnerability particularly dangerous as it can disrupt critical infrastructure operations. The affected web server functionality serves as the primary interface for device configuration and management, rendering this weakness a significant threat to operational continuity.
The technical implementation of this vulnerability stems from improper input validation within the HTTP request processing pipeline. When a remote attacker sends a GET request to the specific URI path "/MOXA_CFG.ini" without including a cookie header, the web server application fails to properly handle the missing authentication context. This condition triggers a null pointer dereference error in the application's memory management routines, causing the web server process to crash and terminate unexpectedly. The flaw demonstrates characteristics consistent with CWE-476 which describes null pointer dereference vulnerabilities, where the application fails to check for null values before attempting to access memory locations. The absence of proper null checks in the request handling code creates an exploitable path that directly leads to process termination.
The operational impact of this vulnerability extends beyond simple service interruption as it affects industrial control systems where device availability directly correlates to production uptime. Network administrators responsible for maintaining these devices face potential operational disruptions that could cascade through industrial processes, particularly in manufacturing environments where continuous operation is essential. The vulnerability requires minimal exploitation effort as it only necessitates a simple HTTP GET request without authentication, making it highly accessible to attackers. This characteristic aligns with ATT&CK technique T1499 which covers network denial of service attacks, where adversaries leverage application-level weaknesses to disrupt services. The vulnerability's accessibility means that even unskilled attackers could potentially cause service disruption, increasing the overall risk to industrial networks.
Mitigation strategies for this vulnerability should prioritize immediate firmware updates from Moxa to address the underlying null pointer dereference issue. Network administrators should implement access controls and firewall rules to restrict access to the affected device's web interface, particularly limiting access to trusted administrative networks. The implementation of intrusion detection systems can help identify suspicious HTTP request patterns targeting the specific URI path, providing early warning of potential exploitation attempts. Additionally, network segmentation practices should isolate industrial control systems from general network access to minimize the attack surface. Security monitoring should include regular vulnerability assessments targeting industrial control system components to identify similar weaknesses in other networked devices. The remediation process must consider the operational impact of firmware updates, ensuring that critical industrial processes maintain availability during the patching cycle while addressing the identified denial of service vulnerability.