CVE-2017-14428 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/run/hostapd* permissions.
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Analysis
by VulDB Data Team • 11/15/2019
The vulnerability identified as CVE-2017-14428 affects D-Link DIR-850L wireless routers across multiple firmware revisions, specifically targeting the hostapd service configuration files. This issue represents a critical misconfiguration that exposes sensitive system components to unauthorized access through overly permissive file permissions. The affected devices operate with world-writable permissions set on the /var/run/hostapd* files, which are essential for managing wireless access point operations and authentication processes. This misconfiguration creates a fundamental security weakness that can be exploited by local attackers to manipulate core wireless networking functionality.
The technical flaw stems from improper permission settings on runtime configuration files used by the hostapd daemon, which manages wireless access point services on the device. When files are set with 0666 permissions, they become accessible for reading, writing, and executing by all users on the system, including unprivileged local accounts. This misconfiguration allows attackers to modify wireless network parameters, inject malicious configuration data, or potentially escalate privileges through manipulation of these runtime files. The vulnerability exists at the file system level and represents a failure in proper privilege separation and access control implementation.
The operational impact of this vulnerability extends beyond simple permission misconfiguration, as it enables attackers to compromise the wireless access point functionality and potentially gain deeper system access. Local attackers can exploit this weakness to modify wireless network settings, change authentication parameters, or inject malicious configurations that could lead to unauthorized network access. The hostapd service controls critical wireless networking functions including authentication protocols, encryption settings, and client management, making these files prime targets for exploitation. This vulnerability directly impacts the device's ability to maintain secure wireless communications and can result in unauthorized network access or complete compromise of the wireless infrastructure.
Security mitigations for this vulnerability involve immediate remediation through proper file permission configuration, ensuring that sensitive runtime files are set with restrictive permissions such as 0600 or 0640 to limit access to authorized processes only. Network administrators should update firmware to versions that address this permission issue and implement regular security audits to verify proper file permissions across all system components. The vulnerability aligns with CWE-732: Incorrect Permission Assignment for Critical Resource and represents a clear violation of the principle of least privilege. From an ATT&CK perspective, this weakness maps to T1068: Exploitation for Privilege Escalation and T1078: Valid Accounts, as it provides a mechanism for local privilege escalation through file system manipulation. Organizations should also implement automated monitoring solutions to detect unauthorized permission changes and maintain comprehensive network segmentation to limit the potential impact of such local exploitation vectors.