CVE-2018-17440 in Central WiFi Manager
Summary
by MITRE
An issue was discovered on D-Link Central WiFi Manager before v 1.03r0100-Beta1. They expose an FTP server that serves by default on port 9000 and has hardcoded credentials (admin, admin). Taking advantage of this, a remote unauthenticated attacker could execute arbitrary PHP code by uploading any file in the web root directory and then accessing it via a request.
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Analysis
by VulDB Data Team • 04/14/2025
The vulnerability identified as CVE-2018-17440 affects D-Link Central WiFi Manager versions prior to 1.03r0100-Beta1, representing a critical security flaw that exposes the device to remote exploitation. This issue stems from the improper configuration of the device's FTP service, which operates on port 9000 by default and utilizes hardcoded credentials consisting of the username 'admin' and password 'admin'. The presence of such default credentials creates an immediate and severe attack surface that allows unauthorized access to the system's file upload functionality. The vulnerability is classified under CWE-798 as the use of hardcoded credentials, which directly violates security best practices and creates a persistent weakness that remains exploitable across device reboots.
The technical exploitation of this vulnerability involves a multi-stage attack vector that begins with the attacker's ability to connect to the exposed FTP service using the hardcoded credentials. Once authenticated, the attacker can upload arbitrary files to the web root directory of the device, effectively bypassing normal file upload restrictions. The critical aspect of this vulnerability lies in the fact that the uploaded PHP files can be executed directly by the web server, providing a direct code execution capability. This represents a classic file upload vulnerability that enables remote code execution, allowing attackers to execute malicious commands on the target system. The attack chain follows the typical pattern of credential compromise followed by file upload and execution, which aligns with ATT&CK technique T1105 for remote file execution.
The operational impact of this vulnerability is severe and multifaceted, as it provides attackers with complete control over the affected device. Remote unauthenticated attackers can execute arbitrary PHP code, which may lead to complete system compromise, data exfiltration, and potential lateral movement within network environments. The hardcoded credentials make this vulnerability particularly dangerous because they remain unchanged across device reboots, ensuring persistent access for attackers who discover them. This vulnerability affects network infrastructure devices that are typically deployed in enterprise environments, where such compromises can lead to significant security breaches and unauthorized access to sensitive network resources. The default configuration of the device without proper authentication mechanisms creates an environment where attackers can gain system-level privileges without requiring any specialized knowledge or additional attack vectors.
Mitigation strategies for this vulnerability should focus on immediate remediation actions and long-term configuration improvements. The primary recommendation is to update the D-Link Central WiFi Manager to version 1.03r0100-Beta1 or later, which addresses the hardcoded credential issue and implements proper authentication mechanisms. Network administrators should disable the FTP service entirely if it is not required for legitimate operations, as the service represents an unnecessary attack surface. Additionally, implementing network segmentation and access controls can limit the potential impact of such vulnerabilities by restricting access to the device to authorized personnel only. Security monitoring should be enhanced to detect unauthorized FTP connections and file upload activities, while regular security audits should verify that no hardcoded credentials exist in the system configuration. The vulnerability serves as a reminder of the importance of secure default configurations and the necessity of implementing proper authentication and authorization mechanisms in network devices, aligning with security standards such as those outlined in NIST SP 800-53 and ISO 27001 requirements for secure system design and configuration management.