CVE-2017-7929 in WebAccess
Summary
by MITRE
An Absolute Path Traversal issue was discovered in Advantech WebAccess Version 8.1 and prior. The absolute path traversal vulnerability has been identified, which may allow an attacker to traverse the file system to access restricted files or directories.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 12/22/2020
The CVE-2017-7929 vulnerability represents a critical absolute path traversal flaw in Advantech WebAccess version 8.1 and earlier implementations. This vulnerability resides within the web application's file handling mechanisms, specifically in how it processes user-supplied input when accessing files or directories. The flaw allows malicious actors to manipulate file path parameters in a way that bypasses normal access controls and navigates to arbitrary locations within the file system. This type of vulnerability falls under the category of CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The vulnerability is particularly concerning because it affects industrial control systems where WebAccess serves as a web-based interface for monitoring and controlling industrial processes.
The technical exploitation of this vulnerability occurs when the application fails to properly validate or sanitize user input that is used to construct file paths. Attackers can craft malicious requests containing sequences such as "../" or similar path manipulation techniques to move up directory levels and access files outside the intended web root or application directory. The vulnerability is particularly dangerous because it allows attackers to access sensitive configuration files, authentication credentials, system logs, and potentially even executable code that could lead to further compromise of the industrial control environment. This type of attack aligns with ATT&CK technique T1071.004, which covers application layer protocol manipulation, and T1566, which addresses credential access through various attack vectors.
The operational impact of CVE-2017-7929 extends beyond simple unauthorized file access, as it can potentially lead to complete system compromise within industrial environments. In industrial control systems where WebAccess is deployed, attackers could gain access to critical operational data, disrupt processes, or even manipulate control systems by accessing configuration files that govern industrial processes. The vulnerability affects the confidentiality, integrity, and availability of industrial control systems, making it particularly dangerous in environments where operational technology (OT) security is paramount. Organizations using affected versions of Advantech WebAccess face significant risk of unauthorized access to proprietary industrial processes, sensitive operational data, and potentially critical infrastructure control mechanisms. The attack surface is particularly broad in industrial environments where multiple systems may be interconnected through WebAccess interfaces.
Mitigation strategies for this vulnerability require immediate patching of affected systems to the latest version of Advantech WebAccess that addresses the path traversal issue. Organizations should implement network segmentation to limit access to WebAccess interfaces and apply strict access controls to prevent unauthorized users from reaching vulnerable endpoints. Input validation and sanitization mechanisms should be strengthened to ensure that all user-supplied path parameters are properly validated before being used in file system operations. Security monitoring should be enhanced to detect suspicious file access patterns that may indicate exploitation attempts. Additionally, organizations should conduct comprehensive security assessments of their industrial control systems to identify other potential vulnerabilities that could be exploited in conjunction with path traversal attacks. The remediation process should include regular vulnerability scanning and penetration testing to ensure that similar issues are not present in other components of the industrial control infrastructure.