CVE-2020-7567 in Modicon M221
Summary
by MITRE • 11/20/2020
A CWE-311: Missing Encryption of Sensitive Data vulnerability exists in Modicon M221 (all references, all versions) that could allow the attacker to find the password hash when the attacker has captured the traffic between EcoStruxure Machine - Basic software and Modicon M221 controller and broke the encryption keys.
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Analysis
by VulDB Data Team • 05/30/2026
The vulnerability identified as CVE-2020-7567 represents a critical weakness in the Modicon M221 controller series, specifically classified under CWE-311: Missing Encryption of Sensitive Data. This vulnerability manifests within the EcoStruxure Machine - Basic software ecosystem where communication occurs between the host software and the Modicon M221 controller. The flaw stems from insufficient protection of sensitive data during transmission, creating an exploitable condition that directly impacts the security posture of industrial control systems. The vulnerability affects all versions and references of the Modicon M221 controller, making it a widespread concern across deployed industrial infrastructure.
The technical implementation of this vulnerability occurs at the network communication layer where authentication credentials and password hashes are transmitted without adequate encryption. When an attacker successfully captures network traffic between the EcoStruxure Machine - Basic software and the Modicon M221 controller, they can potentially intercept and analyze the communication streams. The vulnerability becomes particularly dangerous when combined with successful cryptographic key breaking attempts, which allows threat actors to decrypt and extract sensitive authentication information. This weakness directly violates fundamental security principles of data protection in transit and represents a significant gap in the industrial cybersecurity framework.
The operational impact of CVE-2020-7567 extends beyond simple credential theft to encompass potential system compromise and operational disruption. Attackers who successfully exploit this vulnerability gain access to password hashes that can be used for lateral movement within industrial networks, potentially leading to unauthorized access to critical control systems. The vulnerability creates a pathway for attackers to escalate privileges and gain deeper access to industrial control environments, particularly in scenarios where multiple controllers share similar authentication mechanisms. This threat vector aligns with ATT&CK technique T1078.004 which covers valid accounts through compromised credentials, representing a common attack pattern in industrial control system environments.
Mitigation strategies for this vulnerability require immediate implementation of robust encryption protocols and network security measures. Organizations should implement strong encryption standards for all communication between industrial software and controllers, ensuring that authentication data is protected using industry-standard cryptographic methods such as TLS 1.3 or higher. Network segmentation and monitoring should be deployed to detect and prevent unauthorized traffic capture attempts. The vulnerability also highlights the importance of regular security assessments and firmware updates, as recommended by NIST SP 800-82 guidelines for industrial control systems. Additionally, implementing network access controls and credential management best practices can significantly reduce the attack surface and prevent exploitation of this specific weakness in the Modicon M221 controller ecosystem.