CVE-2016-9364 in FX-20
Summary
by MITRE
An issue was discovered in Fidelix FX-20 series controllers, versions prior to 11.50.19. Arbitrary file reading via path traversal allows an attacker to access arbitrary files and directories on the server.
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Analysis
by VulDB Data Team • 08/14/2020
The vulnerability identified as CVE-2016-9364 affects Fidelix FX-20 series controllers running versions prior to 11.50.19, representing a critical path traversal flaw that enables unauthorized file access. This vulnerability resides within the web interface of the controller software, where insufficient input validation allows attackers to manipulate file paths and gain access to sensitive system files that should remain restricted. The flaw manifests when the application fails to properly sanitize user-supplied input before using it in file system operations, creating an opportunity for malicious actors to traverse directory structures beyond the intended scope.
The technical implementation of this vulnerability stems from improper input validation mechanisms within the controller's web server component. When users submit requests containing file path parameters, the system does not adequately filter or sanitize these inputs, allowing attackers to inject sequences such as "../" or similar directory traversal patterns. This weakness directly maps to CWE-22, which categorizes path traversal vulnerabilities as a fundamental flaw in input validation that permits unauthorized access to restricted directories. The vulnerability operates at the application layer and can be exploited through HTTP requests that manipulate file access parameters, making it particularly dangerous as it requires no special privileges or authentication to exploit.
The operational impact of this vulnerability extends beyond simple information disclosure, as attackers can potentially access configuration files, system logs, authentication credentials, and other sensitive data stored within the controller's file system. This exposure creates a significant risk for industrial control systems where the FX-20 series controllers are deployed, as the compromised information could reveal network topology, operational parameters, or even enable further escalation attacks. The vulnerability affects the confidentiality and integrity of the system, potentially allowing attackers to gain insights into the operational environment that could be leveraged for more sophisticated attacks. Organizations relying on these controllers for critical infrastructure operations face substantial risk from this flaw, particularly in environments where physical security measures may be insufficient to prevent unauthorized network access.
Mitigation strategies for CVE-2016-9364 should prioritize immediate patching of affected systems to version 11.50.19 or later, which includes proper input validation and sanitization mechanisms. Network segmentation and access control measures should be implemented to limit exposure of the affected controllers to untrusted networks, while monitoring systems should be configured to detect suspicious file access patterns. Security teams should also consider implementing web application firewalls to filter out potentially malicious path traversal attempts and establish regular vulnerability assessment procedures to identify similar weaknesses in other industrial control systems. The remediation process must include comprehensive testing to ensure that the patch does not introduce compatibility issues with existing operational procedures, and organizations should conduct security awareness training for personnel responsible for maintaining these critical systems. Additionally, the vulnerability highlights the importance of applying security patches promptly, as the timeframe between vulnerability disclosure and exploitation can be relatively short in industrial environments where system downtime is costly and security updates may not be applied immediately.