CVE-2017-7574 in SoMachine Basic
Summary
by MITRE
Schneider Electric SoMachine Basic 1.4 SP1 and Schneider Electric Modicon TM221CE16R 1.3.3.3 devices have a hardcoded-key vulnerability. The Project Protection feature is used to prevent unauthorized users from opening an XML protected project file, by prompting the user for a password. This XML file is AES-CBC encrypted; however, the key used for encryption (SoMachineBasicSoMachineBasicSoMa) cannot be changed. After decrypting the XML file with this key, the user password can be found in the decrypted data. After reading the user password, the project can be opened and modified with the Schneider product.
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Analysis
by VulDB Data Team • 05/29/2026
The vulnerability identified as CVE-2017-7574 represents a critical security flaw in Schneider Electric's industrial automation products, specifically affecting SoMachine Basic 1.4 SP1 and Modicon TM221CE16R 1.3.3.3 devices. This weakness stems from the implementation of a hardcoded encryption key within the Project Protection mechanism, creating a fundamental flaw in the security architecture that undermines the intended access controls. The vulnerability operates at the application layer and directly impacts the confidentiality and integrity of industrial control system projects, making it particularly dangerous in operational technology environments where security is paramount.
The technical implementation of this vulnerability involves the use of AES-CBC encryption with a fixed, unchangeable key value "SoMachineBasicSoMachineBasicSoMa" that is embedded within the software itself. This hardcoded key eliminates any possibility for administrators to customize or strengthen the encryption parameters, effectively creating a universal decryption key that can be discovered through reverse engineering or by examining the software binaries. The encryption process is designed to protect XML project files, but the hardcoded nature of the key means that any attacker with access to the system can decrypt these files without proper authorization, bypassing the intended password protection mechanism entirely.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as it fundamentally compromises the security model of industrial control systems. An attacker who discovers the hardcoded key can not only access protected project files but can also modify them, potentially introducing malicious code or altering control logic that could affect industrial processes. This vulnerability aligns with CWE-320, which addresses weaknesses related to the use of hard-coded cryptographic keys, and represents a significant risk in environments where these devices operate, as it eliminates the ability to maintain secure access controls for critical industrial automation projects. The implications are particularly severe in environments where these devices control manufacturing processes, power generation, or other critical infrastructure where unauthorized modifications could lead to operational disruptions or safety hazards.
Organizations affected by this vulnerability should implement immediate mitigations including disabling the Project Protection feature when possible, implementing network segmentation to limit access to these devices, and conducting thorough security assessments of their industrial control systems. The recommended approach involves updating to patched versions of the software where available, as this vulnerability specifically relates to the encryption implementation rather than network protocols or other attack vectors. Additionally, administrators should consider implementing additional access controls and monitoring mechanisms to detect unauthorized access attempts, as the hardcoded key vulnerability creates a persistent risk that cannot be resolved through configuration changes alone. This vulnerability demonstrates the critical importance of avoiding hardcoded credentials in security implementations and serves as a reminder of the potential consequences when cryptographic keys are embedded within software rather than being dynamically generated or managed through secure key management processes.