## 3 Proposed Approach
### Network Layer Attacks and Countermeasures  
The network layer is fundamental to SCADA and physical systems, enabling the continuous real-time data exchange critical to operations. However, the openness and central role of the network layer make it inherently vulnerable to cyber threats, particularly malware that exploits network connectivity to infiltrate and disrupt interconnected systems. Therefore, securing the network layer is essential for safeguarding SCADA and ICSs from malicious disruptions that could lead to broader infrastructure failures. To enhance network layer security, organizations can implement multi-layered countermeasures, including VLAN segmentation and AI-powered IDSs. VLAN segmentation isolates network segments, effectively limiting lateral malware movement and preventing uncontrolled spread across systems. This strategy ensures that a single compromised segment does not lead to a full-scale breach. Additionally, an AI-powered IDS leverages machine learning algorithms to continuously analyze network behavior, identifying unusual traffic patterns indicative of unauthorized access or malicious activities. When such anomalies are detected, the IDS generates real-time alerts, enabling swift containment measures. A prominent example of network layer vulnerability is the Triton malware attack, which exploited weaknesses in SCADA and Safety Instrumented Systems (SISs), allowing attackers to manipulate industrial processes. By infiltrating the network layer, Triton propagated across the SCADA and SIS components, compromising the physical infrastructure's integrity and functionality. This underscores the high stakes involved in securing the network layer, where cyberattacks can have consequences beyond digital disruptions, impacting the physical world. In addition to technical weaknesses, the network layer is also susceptible to human-based risks, such as insider threats and social engineering attacks. Insiders, whether through negligence or malicious intent, may compromise network security, while phishing and social engineering tactics can trick network administrators into clicking malicious links or downloading infected files. Once malware enters the network through these means, it can spread rapidly, particularly if security mechanisms are disabled or bypassed. Thus, network security requires addressing both technical and human vulnerabilities. To mitigate these risks, organizations should implement behavior monitoring and anomaly detection systems that identify unusual access patterns or suspicious activity in real time. By continuously tracking network activities and flagging deviations from established norms, these systems detect malicious insider activities or external attacks early, allowing for a proactive response. Additionally, training programs that raise awareness of social engineering tactics help personnel recognize and respond appropriately to potential threats. Together, these approaches strengthen network layer resilience, reducing the risk of widespread disruptions and protecting critical operations. According to Figure 4, the diagram illustrates the process of detecting and responding to abnormal traffic in the network layer. When abnormal traffic is identified, the traffic monitoring system analyzes the irregularities, and the IDS promptly detects the issue and alerts administrators. Network segmentation further prevents malicious traffic from spreading to other computers within the network, minimizing the overall impact of the malware. To address network vulnerabilities effectively, the following measures should be implemented:* Implement an IDS to monitor network traffic in real time and detect abnormal traffic, issuing alerts when anomalies are found. * Apply network segmentation to prevent malware from spreading to other networks in case of infection, limiting the impact of any potential breaches.