CVE-2019-13532 in CODESYS V3
Summary
by MITRE
CODESYS V3 web server, all versions prior to 3.5.14.10, allows an attacker to send specially crafted http or https requests which may allow access to files outside the restricted working directory of the controller.
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Analysis
by VulDB Data Team • 12/25/2023
The vulnerability identified as CVE-2019-13532 affects CODESYS V3 web server implementations across all versions prior to 3.5.14.10, representing a critical directory traversal flaw that exposes systems to unauthorized file access. This weakness stems from inadequate input validation within the web server component, specifically in how it processes HTTP and HTTPS requests containing specially crafted paths that manipulate the working directory restrictions. The flaw allows attackers to bypass the intended security boundaries that should contain file access within the controller's designated working directory, potentially enabling access to sensitive system files, configuration data, and other restricted resources.
The technical implementation of this vulnerability demonstrates a classic path traversal attack vector where malicious input can manipulate the web server's file resolution mechanism. When the web server processes requests containing sequences such as ../ or similar directory navigation patterns, it fails to properly sanitize these inputs before resolving file paths. This allows an attacker to craft requests that traverse up the directory structure beyond the intended working directory boundaries. The vulnerability operates at the application layer and affects the web server functionality that handles HTTP and HTTPS protocols, making it particularly dangerous in industrial control systems where CODESYS V3 is commonly deployed.
From an operational impact perspective, this vulnerability poses significant risks to industrial environments that rely on CODESYS V3 for controller management and web-based access. Attackers who successfully exploit this flaw can potentially access sensitive configuration files, system logs, firmware images, and other critical data that should remain isolated within the controller's restricted environment. The implications extend beyond simple information disclosure, as unauthorized access to controller files could enable attackers to gain deeper insights into system architecture, potentially leading to more sophisticated attacks targeting the industrial control infrastructure. This vulnerability directly impacts the principle of least privilege and can undermine the security boundaries designed to protect critical industrial systems from external threats.
The vulnerability aligns with CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. This weakness is categorized under the broader ATT&CK framework as part of the Credential Access and Defense Evasion tactics, where adversaries attempt to gain access to sensitive files and data without detection. Organizations implementing CODESYS V3 should prioritize immediate remediation through the official update to version 3.5.14.10 or later, which includes proper input validation and path sanitization mechanisms. Additional mitigations include implementing network segmentation, restricting web server access to trusted networks, and deploying web application firewalls that can detect and block suspicious path traversal patterns in HTTP requests. Regular security assessments and monitoring of web server access logs should also be implemented to detect potential exploitation attempts and ensure the continued integrity of industrial control systems.