CVE-2018-7798 in Modicon M221
Summary
by MITRE
A Insufficient Verification of Data Authenticity (CWE-345) vulnerability exists in the Modicon M221, all versions, which could cause a change of IPv4 configuration (IP address, mask and gateway) when remotely connected to the device.
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Analysis
by VulDB Data Team • 05/29/2026
The vulnerability identified as CVE-2018-7798 represents a critical weakness in the Modicon M221 programmable logic controller that falls under the CWE-345 category of insufficient verification of data authenticity. This flaw specifically impacts all versions of the Modicon M221 device, creating a significant security risk for industrial control systems that rely on this equipment for critical operations. The vulnerability manifests when remote connections are established to the device, allowing unauthorized parties to manipulate fundamental network parameters that govern how the controller communicates within industrial networks.
The technical implementation of this vulnerability stems from inadequate authentication mechanisms during remote communication sessions. When an attacker successfully establishes a remote connection to the Modicon M221 device, they can exploit the insufficient verification processes to alter the device's IPv4 configuration parameters including IP address, subnet mask, and default gateway settings. This manipulation occurs without proper validation of the connection source or the authenticity of the data being transmitted, creating a pathway for malicious actors to disrupt network communications and potentially gain further access to the industrial control environment.
The operational impact of this vulnerability extends beyond simple network configuration changes, as it fundamentally undermines the integrity and availability of industrial control systems. By modifying the IPv4 configuration, an attacker can effectively isolate the device from its intended network segment, redirect traffic to malicious endpoints, or create denial of service conditions that prevent legitimate operators from accessing critical control functions. This vulnerability particularly concerns industrial environments where network stability and predictable communication patterns are essential for maintaining operational continuity and safety protocols.
From a cybersecurity perspective, this vulnerability aligns with several ATT&CK framework techniques including T1071.004 Application Layer Protocol and T1046 Network Service Scanning, as it enables attackers to manipulate network communications and potentially escalate privileges within the industrial control system. The weakness creates opportunities for lateral movement within industrial networks, as compromised devices can serve as launching points for further attacks against other connected systems. Organizations implementing the Modicon M221 should consider this vulnerability in their risk assessments and ensure appropriate network segmentation and access controls are in place to limit the potential impact of such attacks.
Mitigation strategies for CVE-2018-7798 should focus on implementing robust authentication mechanisms, network segmentation, and monitoring of network configuration changes. Organizations should enforce strong access controls for remote connections, deploy network monitoring solutions that can detect unauthorized configuration changes, and ensure that all Modicon M221 devices are updated with the latest firmware releases from Schneider Electric. Additionally, implementing network access control lists and regular security audits can help identify and prevent exploitation attempts. The vulnerability demonstrates the importance of applying security controls throughout the industrial control system lifecycle, particularly in environments where network configuration changes can have cascading effects on operational safety and system availability.