CVE-2017-14425 in DIR-850L
Summary
by MITRE
D-Link DIR-850L REV. A (with firmware through FW114WWb07_h2ab_beta1) and REV. B (with firmware through FW208WWb02) devices have 0666 /var/etc/hnapasswd permissions.
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Analysis
by VulDB Data Team • 11/15/2019
The vulnerability identified as CVE-2017-14425 affects D-Link DIR-850L wireless routers across multiple firmware versions, presenting a critical access control flaw that compromises the device's security posture. This issue manifests through improper file permissions on the hnapasswd configuration file located at /var/etc/hnapasswd, where the file is accessible with read and write permissions for all users on the system. The affected firmware versions include FW114WWb07_h2ab_beta1 for revision A devices and FW208WWb02 for revision B devices, indicating a widespread vulnerability across multiple product iterations.
The technical flaw stems from inadequate privilege separation and file permission management within the router's firmware implementation. The 0666 permissions assigned to /var/etc/hnapasswd represent a severe deviation from security best practices, as this file contains hashed password credentials for the router's administrative interface. The octal permission value 0666 grants read and write access to all users, including unprivileged system accounts and potentially malicious actors who may have gained access through other attack vectors. This misconfiguration directly violates the principle of least privilege and creates an immediate path for unauthorized access to router administrative functions.
The operational impact of this vulnerability extends beyond simple credential exposure, as it enables attackers to escalate privileges and gain complete control over affected router configurations. The compromised hnapasswd file allows unauthorized users to authenticate as administrators, potentially leading to complete network compromise through configuration changes, DNS hijacking, traffic interception, or the installation of persistent backdoors. This vulnerability particularly affects enterprise and home users who may not regularly update their router firmware, leaving them exposed to automated scanning and exploitation campaigns that target known vulnerabilities in consumer networking equipment.
Security professionals should consider this vulnerability in the context of the CWE-732 category, which addresses inadequate permissions for critical security resources, and aligns with ATT&CK techniques related to privilege escalation and credential access. The vulnerability represents a fundamental failure in the router's security architecture, where basic file permission controls are not properly enforced. Organizations should implement immediate mitigations including firmware updates from D-Link, manual permission correction of the affected file, and network segmentation to limit exposure. The vulnerability also highlights the importance of regular firmware auditing and the need for manufacturers to implement proper access control mechanisms in embedded networking devices, particularly those handling authentication credentials. Network administrators should monitor for exploitation attempts through intrusion detection systems and consider implementing additional security controls such as secure remote access protocols and regular vulnerability assessments of network infrastructure components.