CVE-2016-7826 in WNC01WH
Summary
by MITRE
Directory traversal vulnerability in Buffalo WNC01WH devices with firmware version 1.0.0.8 and earlier allows authenticated attackers to read arbitrary files via specially crafted POST requests.
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Analysis
by VulDB Data Team • 10/15/2019
The CVE-2016-7826 vulnerability represents a critical directory traversal flaw affecting Buffalo WNC01WH wireless network controllers running firmware versions 1.0.0.8 and earlier. This vulnerability resides in the device's web interface implementation where insufficient input validation permits attackers to manipulate file path parameters through crafted POST requests. The flaw stems from the device's failure to properly sanitize user-supplied data before processing file system operations, creating an exploitable condition that allows unauthorized access to sensitive system files. The vulnerability is classified as a directory traversal attack pattern that falls under CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory. This weakness enables attackers to bypass normal access controls and retrieve files that should remain protected within the device's file system hierarchy.
The technical exploitation of this vulnerability requires an authenticated attacker who has already gained access to the device's administrative interface through valid credentials. Once authenticated, the attacker can submit specially crafted POST requests containing directory traversal sequences such as ../ or ..\ that manipulate the file path resolution mechanism. These requests exploit the device's insufficient input validation by allowing path traversal characters to be processed directly without proper sanitization or normalization. The attack vector specifically targets the web application layer where user inputs are directly incorporated into file system operations without adequate security controls. This flaw essentially allows an attacker to navigate beyond the intended directory boundaries and access files such as configuration files, system logs, or potentially even credential storage areas that contain sensitive information.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with access to potentially sensitive system data that could be used for further exploitation. An attacker who successfully exploits this vulnerability could gain access to device configuration files that may contain network credentials, wireless security keys, or other administrative information. The exposure of such data could lead to complete network compromise, as attackers might obtain access to other network resources or use the stolen credentials to escalate privileges. The vulnerability affects the confidentiality and integrity aspects of the CIA triad, as it enables unauthorized data access and potentially allows for data manipulation through the ability to read system files that may contain configuration parameters or access control information. This represents a significant risk to network security posture, particularly in environments where these devices serve as critical network infrastructure components.
Mitigation strategies for CVE-2016-7826 should prioritize firmware updates from Buffalo to address the directory traversal vulnerability, as this represents the most direct and effective solution. Organizations should implement network segmentation and access controls to limit exposure of these devices to authenticated users only, thereby reducing the attack surface. Network monitoring should be enhanced to detect unusual patterns of file access attempts or directory traversal sequences in web traffic. The implementation of web application firewalls and input validation controls can help prevent malicious requests from reaching the vulnerable application layer. Additionally, regular security assessments should include verification of firmware versions and patch compliance to ensure that all devices are running patched versions. This vulnerability aligns with ATT&CK technique T1083, which describes discovery of file and directory permissions, and T1566, which covers credential access through various attack vectors including exploitation of software vulnerabilities. Organizations should also consider implementing principle of least privilege access controls and regular credential rotation to minimize the impact of potential credential exposure through this vulnerability.