The automotive industry is increasingly dependent on broad and complex supply chains as electrification and connectivity advance. The conventional mindset of protecting only one’s own company is no longer sufficient, as attackers exploit weak points and target entire supply chains. Risks are diversifying, ranging from the suspension of parts procurement and logistics, to malicious software or vulnerabilities introduced via software vendors, and even insider threats at contractors—some cases have already led to business disruption. In response to this situation, Japan’s Ministry of Economy, Trade and Industry (METI) plans to launch a “Security Evaluation Scheme for Supply Chain Reinforcement” starting in fiscal year 2026. Collaborative defense and industry-wide risk management have therefore become indispensable. This lecture will provide an overview of recent attack trends and explain the key points of practical countermeasures and operational approaches.