# Adversarial Systems **Entity class:** Systems-security field ## Definition **Adversarial systems** are environments in which intelligent opponents observe defenses, search for weaknesses, adapt behavior, conceal intent, and alter attack paths in response to controls. Counterterrorism and cybersecurity converge at this level because both defend complex systems against adaptive exploitation. ## Relevance to this collection It connects [[wiki/Counterterrorism-Cybersecurity Convergence|Counterterrorism–Cybersecurity Convergence]], [[wiki/Sociotechnical Attack Surface|Sociotechnical Attack Surface]], [[wiki/Adversarial Adaptation|Adversarial Adaptation]], and [[wiki/Predictive Defense|Predictive Defense]]. ## Relationships - **master collection:** [[collections/Terrorism, Counterterrorism, and the Intelligence Environment|Terrorism, Counterterrorism, and the Intelligence Environment]]. ## Sources / Provenance - [U.S. Department of Defense, *2023 Cyber Strategy Summary*, September 12, 2023](https://media.defense.gov/2023/Sep/12/2003299076/-1/-1/1/2023_DOD_CYBER_STRATEGY_SUMMARY.PDF). **As of:** 2026-09-23