CVE-2016-8371 in ILC PLC
Summary
by MITRE
The web server in Phoenix Contact ILC PLCs can be accessed without authenticating even if the authentication mechanism is enabled.
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Analysis
by VulDB Data Team • 05/30/2025
The vulnerability identified as CVE-2016-8371 affects Phoenix Contact ILC programmable logic controllers where the web server component lacks proper authentication enforcement mechanisms. This weakness resides within industrial control systems that are critical for manufacturing and automation processes, creating a significant security risk for operational technology environments. The affected devices are part of the industrial control system landscape that requires robust security measures to protect against unauthorized access and potential cyber attacks targeting critical infrastructure.
This vulnerability represents a fundamental flaw in the authentication architecture of the web server component, where the system fails to properly validate user credentials even when authentication is explicitly enabled. The technical implementation appears to have a logic error or configuration oversight that allows unauthenticated access to web-based management interfaces. This issue falls under the category of weak authentication mechanisms and can be classified as a CWE-287 weakness related to improper authentication. The vulnerability demonstrates a critical failure in the principle of least privilege, where system administrators cannot rely on authentication mechanisms to prevent unauthorized access to sensitive control system functions.
The operational impact of this vulnerability extends beyond simple unauthorized access to potentially compromise entire industrial control processes. Attackers who gain access to the web server interface can manipulate programmable logic controller settings, view sensitive operational data, and potentially cause disruptions to manufacturing processes or safety systems. This vulnerability directly affects the confidentiality, integrity, and availability of industrial control systems, which are fundamental pillars of cybersecurity in critical infrastructure environments. The risk is amplified in environments where these controllers manage safety-critical processes, as unauthorized access could lead to production disruptions, safety hazards, or environmental impacts.
Organizations should implement immediate mitigations including disabling unnecessary web server functionality when not required, enforcing strong network segmentation between control systems and corporate networks, and applying vendor-provided firmware updates when available. The vulnerability highlights the importance of secure configuration management practices and proper security hardening of industrial control systems. From an ATT&CK framework perspective, this vulnerability maps to techniques involving unauthorized access and credential manipulation, potentially enabling further lateral movement within industrial networks. System administrators should also consider implementing network monitoring solutions to detect unauthorized access attempts and establish proper access controls that align with NIST SP 800-82 guidelines for industrial control systems security.