CVE-2020-7565 in Modicon M221
Summary
by MITRE • 11/20/2020
A CWE-326: Inadequate Encryption Strength vulnerability exists in Modicon M221 (all references, all versions) that could allow the attacker to break the encryption key when the attacker has captured the traffic between EcoStruxure Machine - Basic software and Modicon M221 controller.
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Analysis
by VulDB Data Team • 05/30/2026
The CVE-2020-7565 vulnerability represents a critical security flaw in Modicon M221 controllers that falls under CWE-326, which specifically addresses inadequate encryption strength in security implementations. This vulnerability affects all versions and references of the Modicon M221 device, making it a widespread concern for industrial control systems. The flaw manifests when an attacker successfully captures network traffic between the EcoStruxure Machine - Basic software and the Modicon M221 controller, creating an opportunity for cryptographic key recovery attacks. The vulnerability directly impacts the confidentiality and integrity of communication within industrial automation environments where these devices operate.
The technical implementation of this vulnerability stems from insufficient cryptographic strength used in the communication protocols between the supervisory software and the controller. When the EcoStruxure Machine - Basic software establishes communication with the Modicon M221, it employs encryption mechanisms that do not meet contemporary security standards. Attackers who can intercept this network traffic can leverage various cryptanalysis techniques to break the encryption keys, potentially gaining unauthorized access to the controller's operational parameters and control functions. This weakness creates a pathway for attackers to manipulate industrial processes, access sensitive operational data, and potentially cause physical damage to equipment through unauthorized control commands.
The operational impact of this vulnerability extends beyond simple data interception, creating significant risks for industrial environments where Modicon M221 controllers are deployed. Organizations utilizing these controllers in manufacturing, process control, and automation systems face potential exposure to cyber attacks that could result in production disruptions, safety hazards, and financial losses. The vulnerability particularly affects environments where network monitoring and traffic capture capabilities exist, as these conditions enable attackers to gather sufficient data for cryptographic key recovery. From an operational standpoint, this vulnerability undermines the trust model of industrial communication protocols and could lead to cascading failures if attackers exploit the compromised controller to gain access to other connected systems.
Mitigation strategies for CVE-2020-7565 should focus on strengthening the cryptographic implementations within the Modicon M221 controllers and their associated software. Organizations should implement network segmentation to limit the exposure of controller communications to unauthorized parties and deploy intrusion detection systems to monitor for suspicious traffic patterns. The most effective long-term solution involves updating to firmware versions that address the encryption weakness, though vendors should be consulted for specific patch availability and implementation guidance. Additionally, implementing network access controls, employing secure remote access protocols, and conducting regular security assessments of industrial control systems can help reduce the attack surface and prevent exploitation of this vulnerability. This remediation approach aligns with industry best practices for industrial cybersecurity and addresses the fundamental cryptographic weaknesses that enable this class of attack.