This lecture covers the fundamentals of cybersecurity, including the practice of protecting systems, networks, and programs from digital attacks. It delves into the importance of cybersecurity in today's technologically-advanced world, highlighting the alarming statistics of data breaches, hacker attacks, and the significant financial losses incurred. The lecture also explores threat modeling methodologies, risk assessment, and decision-making processes to mitigate cyber threats. Additionally, it discusses various attack vectors, vulnerabilities, and the consequences of cyber-attacks, using real-world case studies like the RUAG cyber espionage incident. The session concludes with insights into digital forensics procedures, attribution, and the human factor in cybersecurity.