CVE-2018-21137 in D3600
Summary
by MITRE
Certain NETGEAR devices are affected by a hardcoded password. This affects D3600 before 1.0.0.76 and D6000 before 1.0.0.76.
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Analysis
by VulDB Data Team • 06/02/2024
The vulnerability identified as CVE-2018-21137 represents a critical security flaw in NETGEAR D3600 and D6000 router models where hardcoded credentials are embedded within the device firmware. This issue stems from poor software development practices where default authentication credentials are permanently coded into the system rather than being dynamically generated or properly secured during the manufacturing process. The affected firmware versions indicate that this vulnerability has persisted across multiple releases, suggesting a fundamental design flaw rather than a one-time coding error. Such hardcoded passwords create an inherent security weakness that exists from the moment the device is manufactured and shipped to end users.
The technical implementation of this vulnerability involves the presence of static username and password combinations within the router's firmware image that cannot be changed by users or administrators. This pattern violates fundamental security principles and creates a persistent attack surface that remains exploitable regardless of user configuration changes or security updates. The vulnerability directly maps to CWE-798, which specifically addresses the use of hardcoded passwords in software systems, and aligns with ATT&CK technique T1078.004 for valid accounts using default credentials. When attackers discover these hardcoded credentials, they gain immediate unauthorized access to the affected devices without requiring any additional exploitation techniques or reconnaissance efforts.
The operational impact of this vulnerability extends beyond simple unauthorized access to include complete network compromise and potential data exfiltration. Once an attacker gains access through the hardcoded credentials, they can modify router configurations, redirect traffic, install malicious firmware, or use the device as a pivot point for attacking other systems within the local network. The D3600 and D6000 models represent consumer and small office networking equipment where users may not regularly update firmware or implement additional security controls, making these devices particularly attractive targets for exploitation. This vulnerability essentially provides an open door for any attacker who can obtain the hardcoded credentials, whether through public documentation, security research, or other means, creating a persistent threat that can affect thousands of devices simultaneously.
Mitigation strategies for this vulnerability require immediate firmware updates from NETGEAR to address the hardcoded credential issue in affected models. Users should verify their router firmware versions and apply patches as soon as they become available, though the nature of hardcoded credentials means that any device shipped with these credentials remains vulnerable until the firmware is updated. Network administrators should implement additional monitoring and access controls to detect unauthorized access attempts, while security teams should conduct comprehensive inventory assessments to identify all affected devices within their networks. The vulnerability highlights the importance of proper credential management practices and the necessity of avoiding hardcoded authentication mechanisms in network infrastructure devices, as outlined in industry standards such as NIST SP 800-53 and ISO 27001 requirements for secure system design and implementation.