CVE-2011-4878 in SIMATIC HMI panel
Summary
by MITRE
Directory traversal vulnerability in miniweb.exe in the HMI web server in Siemens WinCC flexible 2004, 2005, 2007, and 2008 before SP3; WinCC V11 (aka TIA portal) before SP2 Update 1; the TP, OP, MP, Comfort Panels, and Mobile Panels SIMATIC HMI panels; WinCC V11 Runtime Advanced; and WinCC flexible Runtime allows remote attackers to read arbitrary files via a ..%5c (dot dot backslash) in a URI.
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Analysis
by VulDB Data Team • 04/07/2025
The CVE-2011-4878 vulnerability represents a critical directory traversal flaw in Siemens HMI web server implementations that affects multiple versions of WinCC flexible and WinCC V11 products. This vulnerability exists in the miniweb.exe component of the HMI web server, which serves as the primary web interface for various Siemens HMI panels including TP, OP, MP, Comfort Panels, and Mobile Panels. The flaw allows remote attackers to access arbitrary files on the system by exploiting improper input validation in URI handling, specifically through the manipulation of path traversal sequences using the ..%5c encoding pattern where %5c represents the backslash character. This vulnerability impacts a wide range of industrial automation products that rely on Siemens HMI web servers for remote access and configuration management.
The technical exploitation of this vulnerability stems from insufficient validation of user-supplied input in the web server's URI parsing logic. When the miniweb.exe component processes incoming requests containing the ..%5c sequence, it fails to properly sanitize or normalize the path components, allowing attackers to navigate beyond the intended directory structure. This behavior violates fundamental security principles of input validation and access control, creating an arbitrary file read condition that can be leveraged to extract sensitive configuration files, system information, and potentially proprietary industrial control data. The vulnerability is classified under CWE-22 as "Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')", which is a well-established weakness in web application security that has been consistently documented across multiple security frameworks and standards.
The operational impact of CVE-2011-4878 extends beyond simple information disclosure to potentially enable more sophisticated attacks within industrial control systems. Remote attackers could exploit this vulnerability to access system files, configuration data, and potentially gain insights into industrial processes that could be used for further exploitation. In industrial environments, this vulnerability poses significant risks as it could allow unauthorized access to critical control system information, potentially enabling attackers to understand system architecture, identify weak points in control logic, or even manipulate operational parameters. The vulnerability affects both the development environment (WinCC flexible) and runtime environments (WinCC V11 Runtime Advanced), making it particularly concerning for organizations with extensive Siemens HMI deployments. The affected products include various HMI panels that are commonly used in manufacturing and process control environments, where unauthorized access to control system information could compromise operational integrity and safety.
Organizations affected by this vulnerability should prioritize immediate remediation through official Siemens patches and service packs, specifically targeting the SP3 updates for WinCC flexible and SP2 Update 1 for WinCC V11. Network segmentation and access control measures should be implemented to limit exposure of affected systems to untrusted networks, as the vulnerability allows remote exploitation without authentication. Security monitoring should include detection of suspicious URI patterns containing ..%5c sequences in web server logs, which aligns with ATT&CK technique T1071.004 for application layer protocol tunneling and T1566 for credential harvesting through web application attacks. Additionally, organizations should conduct comprehensive vulnerability assessments of their industrial control system environments to identify other potential path traversal vulnerabilities in similar web server implementations and ensure proper input validation controls are in place across all network-accessible components. The vulnerability underscores the importance of maintaining current security patches in industrial environments and demonstrates how legacy industrial systems often contain security flaws that persist across multiple generations of products.