CVE-2016-0855 in WebAccess
Summary
by MITRE
Directory traversal vulnerability in Advantech WebAccess before 8.1 allows remote attackers to list arbitrary virtual-directory files via unspecified vectors.
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Analysis
by VulDB Data Team • 07/23/2018
The vulnerability identified as CVE-2016-0855 represents a directory traversal flaw within Advantech WebAccess software versions prior to 8.1, constituting a critical security weakness that enables remote attackers to access arbitrary virtual directory files through unspecified attack vectors. This vulnerability resides within the web-based management interface of Advantech's industrial automation platform, which is widely deployed in manufacturing and industrial control environments. The directory traversal vulnerability allows an attacker to manipulate file path references and gain unauthorized access to sensitive system files, configuration data, and potentially system directories that should remain protected from external access.
The technical implementation of this flaw stems from inadequate input validation and sanitization within the WebAccess web server components that handle virtual directory requests. When processing user-supplied input for directory navigation, the system fails to properly validate or filter path traversal sequences such as ../ or ..\, enabling attackers to navigate beyond the intended directory boundaries. This weakness aligns with CWE-22, which categorizes directory traversal vulnerabilities as a common class of input validation flaws that occur when applications fail to properly sanitize user input before using it in file system operations. The vulnerability's impact is amplified by the fact that WebAccess is designed for industrial environments where sensitive operational data and system configurations are often stored in accessible locations that could be exploited through this traversal mechanism.
The operational consequences of CVE-2016-0855 extend beyond simple information disclosure, as remote attackers could potentially access system configuration files, user credentials, and other sensitive data that could be leveraged for further compromise. In industrial control systems where WebAccess is deployed, this vulnerability could enable attackers to gain insights into operational procedures, system architecture, and potentially disrupt critical processes by accessing configuration files that control industrial equipment behavior. The attack surface is particularly concerning given that WebAccess is commonly used in environments where physical security and network segmentation may be limited, making remote exploitation more feasible. This vulnerability also aligns with ATT&CK technique T1083, which covers discovery of file and directory permissions, as attackers could use this traversal capability to enumerate system resources and identify potential targets for additional attacks.
Mitigation strategies for this vulnerability should include immediate deployment of Advantech WebAccess version 8.1 or later, which contains the necessary patches to address the directory traversal flaw. Organizations should also implement network segmentation to limit access to WebAccess interfaces, restrict remote access where possible, and deploy web application firewalls that can detect and block suspicious path traversal attempts. Additional security measures include regular security assessments of industrial control system web interfaces, implementation of least privilege access controls, and monitoring for unusual file access patterns that could indicate exploitation attempts. The vulnerability demonstrates the importance of proper input validation in industrial web applications and highlights the need for security testing of critical infrastructure software to prevent similar issues in operational technology environments.