CVE-2017-12124 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 the web server crashing. An attacker can send a crafted URI to trigger this vulnerability.
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Analysis
by VulDB Data Team • 03/13/2023
The vulnerability identified as CVE-2017-12124 represents a critical denial of service weakness within the Moxa EDR-810 V4.1 web server implementation. This device operates as a industrial edge router and remote access solution that provides web-based management interfaces for network administrators. The flaw manifests specifically within the HTTP URI processing functionality where the server fails to properly validate incoming requests before attempting to process them. The affected version Moxa EDR-810 V4.1 build 17030317 contains a programming error that allows maliciously crafted HTTP URIs to trigger a null pointer dereference condition. This particular vulnerability falls under CWE-476 which specifically addresses null pointer dereference issues, making it a well-documented class of weakness that has been prevalent in embedded systems and network appliances for years. The vulnerability exists because the web server component does not adequately validate or sanitize URI parameters before attempting to access memory locations that may be uninitialized or null.
The technical execution of this vulnerability requires an attacker to craft a specific HTTP URI that will cause the web server process to attempt to dereference a null pointer. When the server receives this malformed URI, it attempts to process the request through its internal parsing mechanisms, but encounters a condition where a pointer variable expected to contain valid memory reference becomes null. This null pointer dereference causes the web server process to immediately crash and terminate, resulting in a complete denial of service for the device's web management interface. The impact is particularly severe in industrial environments where the EDR-810 serves as a critical network access point for remote monitoring and management operations. The vulnerability can be exploited remotely without authentication requirements, making it particularly dangerous as any network-connected attacker can trigger the crash simply by sending a specially crafted HTTP request to the device.
The operational implications of this vulnerability extend beyond simple service disruption to potentially compromise industrial control systems and network infrastructure. When the web server crashes, administrators lose access to the device's management interface, which can prevent critical network maintenance operations, configuration changes, and monitoring activities. In environments where the EDR-810 serves as a gateway for industrial protocols and network segmentation, this denial of service can cascade into broader network availability issues. The vulnerability aligns with ATT&CK technique T1499.004 which covers network denial of service attacks, and specifically targets the availability aspect of the CIA triad. The device's role in industrial environments means that such an attack could potentially be leveraged as part of a broader attack chain to disrupt critical infrastructure operations, particularly when combined with other vulnerabilities or attack vectors. The lack of authentication requirements for exploitation makes this vulnerability particularly concerning for devices deployed in unsecured network environments.
Mitigation strategies for this vulnerability should focus on immediate remediation through firmware updates provided by Moxa, which would address the underlying null pointer dereference in the web server implementation. Network administrators should implement network segmentation to limit access to these devices and reduce the attack surface. Additionally, monitoring network traffic for suspicious URI patterns and implementing intrusion detection systems can help identify exploitation attempts. The vulnerability demonstrates the importance of proper input validation and error handling in embedded web servers, particularly those serving critical infrastructure roles. Organizations should also consider implementing redundant access methods for industrial devices to ensure continued operational capability if the primary management interface becomes unavailable. Security best practices recommend regular firmware updates and vulnerability assessments for industrial control systems to prevent exploitation of known weaknesses like those described in CVE-2017-12124.