CVE-2017-14514 in W15E
Summary
by MITRE
Directory Traversal on Tenda W15E devices before 15.11.0.14 allows remote attackers to read unencrypted files via a crafted URL.
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Analysis
by VulDB Data Team • 11/17/2019
The vulnerability identified as CVE-2017-14514 affects Tenda W15E wireless routers running firmware versions prior to 15.11.0.14, representing a critical directory traversal flaw that enables remote attackers to access sensitive unencrypted files on the affected devices. This vulnerability resides in the web interface handling of file paths, where inadequate input validation allows malicious users to manipulate URL parameters to navigate beyond the intended file system boundaries and retrieve arbitrary files from the device's storage. The flaw specifically manifests when the device processes user-supplied URLs without proper sanitization or access controls, creating an exploitable condition that can be leveraged from remote locations without requiring authentication.
The technical implementation of this directory traversal vulnerability stems from improper validation of user-supplied input within the web server component of the router's firmware. Attackers can construct malicious URLs containing sequences such as ../ or ..\ that manipulate the file system navigation paths, allowing them to access files outside of the web root directory. This type of vulnerability is classified under CWE-22 - Improper Limitation of a Pathname to a Restricted Directory and aligns with ATT&CK technique T1213.002 - Data from Information Repositories, specifically targeting the exploitation of web application vulnerabilities to gain unauthorized access to sensitive data. The affected device architecture processes these malformed URLs without implementing proper path validation or canonicalization, enabling attackers to traverse directories and access configuration files, system logs, or other sensitive data that should remain protected.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can lead to complete compromise of the affected router's security posture. Remote attackers can potentially access unencrypted configuration files that may contain administrative credentials, network settings, or other sensitive information that could be used for further exploitation or lateral movement within the network. The vulnerability's remote nature means that attackers can exploit it from anywhere on the internet without requiring physical access to the device, making it particularly dangerous for enterprise and home users who may not regularly update their firmware. Additionally, the lack of authentication requirements for exploitation means that even basic network reconnaissance can reveal the vulnerability, potentially enabling automated scanning tools to identify and exploit multiple devices simultaneously.
Mitigation strategies for CVE-2017-14514 primarily focus on firmware updates and network segmentation measures to reduce the attack surface. Users should immediately update their Tenda W15E devices to firmware version 15.11.0.14 or later, which includes proper input validation and path traversal protection mechanisms. Network administrators should implement firewall rules to restrict access to the router's web management interface from external networks, while also ensuring that internal access is properly authenticated and encrypted. The vulnerability demonstrates the importance of implementing secure coding practices such as input sanitization, proper path validation, and principle of least privilege in web applications. Organizations should also consider deploying intrusion detection systems to monitor for suspicious URL patterns that may indicate exploitation attempts, while maintaining regular vulnerability assessments to identify similar issues in other network devices and applications. The incident underscores the critical need for manufacturers to implement proper security testing and validation procedures during firmware development to prevent such vulnerabilities from reaching production environments.