CVE-2017-9947 in APOGEE PXC
Summary
by MITRE
A vulnerability has been identified in Siemens APOGEE PXC and TALON TC BACnet Automation Controllers in all versions <V3.5. A directory traversal vulnerability could allow a remote attacker with network access to the integrated web server (80/tcp and 443/tcp) to obtain information on the structure of the file system of the affected devices.
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Analysis
by VulDB Data Team • 06/03/2026
The vulnerability identified as CVE-2017-9947 affects Siemens APOGEE PXC and TALON TC BACnet Automation Controllers across all versions prior to V3.5, representing a critical directory traversal flaw within the integrated web server components. This issue stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied data when processing file system requests through the web interface. The vulnerability exists on standard web ports 80/tcp and 443/tcp, making it accessible to remote attackers who can exploit the flaw without requiring physical access or elevated privileges. The affected devices operate within industrial automation environments where network segmentation may be limited, increasing the attack surface and potential impact of this vulnerability.
The technical implementation of this directory traversal vulnerability allows an attacker to manipulate file path parameters through HTTP requests to access files and directories beyond the intended web root. This flaw enables unauthorized information disclosure of the device's file system structure, potentially exposing sensitive configuration files, system binaries, and other critical operational data. The vulnerability directly maps to CWE-22 - Improper Limitation of a Pathname to a Restricted Directory, which is a well-documented weakness in software systems where input validation fails to restrict file access to authorized directories. The flaw represents a fundamental failure in the web server's request handling logic, where relative path traversal sequences such as "../" are not properly filtered or rejected.
From an operational perspective, this vulnerability poses significant risks to industrial control systems that rely on these Siemens controllers for building automation and process control. The information disclosure could enable attackers to gain insights into the controller's internal architecture, potentially revealing system configurations, user credentials, or operational parameters that could facilitate further exploitation. The remote attack vector eliminates the need for physical proximity to the device, making it particularly dangerous in environments where network access is not properly restricted. This vulnerability can be leveraged as a reconnaissance tool by threat actors to plan more sophisticated attacks, including potential privilege escalation or system compromise attempts, aligning with ATT&CK technique T1083 - File and Directory Discovery as part of their reconnaissance phase.
Organizations should immediately implement mitigations including applying the vendor-provided security patches or firmware updates to versions V3.5 and later, which address the directory traversal vulnerability through proper input validation and path sanitization. Network segmentation should be enforced to limit access to the affected devices, with strict firewall rules blocking unnecessary access to ports 80 and 443. Access controls should be implemented to restrict web interface access to authorized personnel only, and regular security audits should be conducted to identify any unauthorized access attempts. The vulnerability highlights the importance of securing industrial web interfaces and demonstrates how seemingly simple input validation flaws can create significant security risks in critical infrastructure environments. Additional monitoring should be implemented to detect unusual file access patterns or directory traversal attempts, and security awareness training should be provided to personnel managing these industrial control systems to recognize potential exploitation attempts.