CVE-2014-0353 in Wireless N300 NetUSB
Summary
by MITRE
The ZyXEL Wireless N300 NetUSB NBG-419N router with firmware 1.00(BFQ.6)C0 allows remote attackers to bypass authentication by using %2F sequences in place of / (slash) characters.
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Analysis
by VulDB Data Team • 05/10/2026
The vulnerability identified as CVE-2014-0353 affects the ZyXEL Wireless N300 NetUSB NBG-419N router running firmware version 1.00(BFQ.6)C0, representing a critical authentication bypass flaw that enables remote attackers to gain unauthorized access to the device's administrative interface. This issue stems from improper input validation within the router's web-based management system, specifically in how it processes URL paths and directory traversal sequences. The vulnerability manifests when attackers substitute standard forward slash characters with URL-encoded %2F sequences, allowing them to circumvent the authentication mechanisms that should protect access to sensitive administrative functions.
The technical flaw resides in the router's handling of Uniform Resource Identifiers within its web interface, where the system fails to properly normalize or sanitize URL-encoded characters before processing access requests. This weakness creates a path traversal vulnerability that can be exploited to access restricted administrative pages without proper authentication credentials. The use of %2F sequences effectively tricks the router's authentication system into treating the encoded characters as legitimate path separators, thereby bypassing the intended access control mechanisms. This type of vulnerability is classified under CWE-22 as Path Traversal, where insufficient input validation allows attackers to manipulate file paths and gain access to restricted resources.
The operational impact of this vulnerability is severe as it provides remote attackers with complete administrative control over the affected router, enabling them to modify network configurations, change administrator passwords, disable security features, and potentially establish persistent access points within the network. Attackers can exploit this vulnerability without requiring any local access or prior authentication credentials, making it particularly dangerous for network administrators who may not immediately detect unauthorized access attempts. The vulnerability affects not only the router's management interface but also potentially exposes the entire network to further attacks, as the compromised device can serve as a pivot point for lateral movement within the network infrastructure.
Mitigation strategies for this vulnerability include immediate firmware updates from ZyXEL to address the authentication bypass flaw, proper network segmentation to limit access to administrative interfaces, and implementation of network monitoring solutions to detect unusual access patterns. Organizations should also enforce strong access controls, including the use of VPNs for administrative access, regular security audits of network devices, and implementation of intrusion detection systems that can identify attempts to exploit URL encoding techniques. The vulnerability aligns with ATT&CK technique T1078.004 for Valid Accounts and T1566.001 for Phishing, as it enables unauthorized access through manipulated authentication sequences and can be leveraged for further network infiltration. Network administrators should also consider implementing web application firewalls to detect and block malicious URL-encoded sequences and ensure that all network devices are regularly updated to address known vulnerabilities.