CVE-2011-4515 in Wincc Tia Portal
Summary
by MITRE
Siemens WinCC (TIA Portal) 11 uses a reversible algorithm for storing HMI web-application passwords in world-readable and world-writable files, which allows local users to obtain sensitive information by leveraging (1) physical access or (2) Sm@rt Server access.
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Analysis
by VulDB Data Team • 01/01/2022
The vulnerability identified as CVE-2011-4515 affects Siemens WinCC (TIA Portal) version 11, a widely used human machine interface software in industrial control systems. This flaw represents a critical security weakness in the software's credential storage mechanisms, where passwords for HMI web applications are stored using a reversible encryption algorithm. The vulnerability specifically impacts the security posture of industrial automation environments where Siemens WinCC is deployed, potentially compromising the integrity and confidentiality of operational technology infrastructure. The issue stems from the software's design decision to store authentication credentials in files that are accessible with world-read and world-write permissions, creating an exploitable attack surface for unauthorized users.
The technical implementation of this vulnerability involves the use of a reversible algorithm for password encryption within the WinCC configuration files. This approach fundamentally undermines security best practices as it allows attackers to easily decrypt stored credentials without requiring sophisticated cryptographic attacks or specialized tools. The reversible nature of the algorithm means that anyone with access to the password storage files can directly retrieve the original passwords, eliminating the need for complex reverse engineering or brute force techniques. This weakness is particularly concerning in industrial environments where physical security controls may be less stringent, as it creates multiple attack vectors for unauthorized access to critical control systems.
The operational impact of CVE-2011-4515 extends beyond simple credential theft, as it provides attackers with potential access to industrial control systems that could be used for malicious activities. Local users with physical access to systems running WinCC can exploit this vulnerability to obtain sensitive information, while remote access via Smrt Server further expands the attack surface. The combination of physical access and Smrt Server exploitation creates a particularly dangerous scenario where attackers can leverage either direct system access or network-based vulnerabilities to compromise system integrity. This vulnerability directly affects the security of industrial control systems and could enable attackers to manipulate process controls, potentially causing operational disruptions or safety hazards in critical infrastructure environments.
The security implications of this vulnerability align with several CWE classifications including CWE-312 (Sensitive Data Exposure) and CWE-259 (Use of Hard-coded Passwords), while also mapping to ATT&CK techniques such as credential access and privilege escalation. Organizations using Siemens WinCC systems should implement immediate mitigations including restricting file permissions to prevent world-readable and world-writable access, implementing proper access controls for physical system access, and conducting comprehensive security assessments of their industrial control environments. The vulnerability highlights the importance of proper cryptographic practices in industrial control systems and underscores the need for robust security controls in operational technology environments where system integrity is paramount.
Organizations should consider implementing network segmentation to limit access to WinCC systems, enforcing strict physical security controls, and regularly auditing system configurations to identify and remediate similar vulnerabilities. The vulnerability also demonstrates the critical importance of secure configuration management in industrial environments where legacy systems may contain inherent security weaknesses that require careful monitoring and mitigation strategies. Proper security awareness training for system administrators and operators is essential to prevent exploitation of such vulnerabilities in production environments.