Defense cybersecurity technologies protect military networks, communication systems, and critical infrastructure from cyberattacks. Challenges include the sophistication of cyber threats, evolving malware, and state-sponsored hacking attempts. Securing defense systems requires continuous monitoring, encryption, intrusion detection, and AI-based anomaly detection. Integrating cybersecurity with operational technology, such as weapons systems, adds complexity. Human errors, supply chain vulnerabilities, and outdated legacy systems further increase risks. Advanced cybersecurity research involves quantum encryption, threat intelligence, and rapid response protocols. Strengthening cybersecurity is crucial for maintaining operational readiness, safeguarding classified information, and ensuring resilience against emerging hybrid warfare that combines cyber and conventional threats.