An after-action report (AAR) is a formal analytical document created following a significant cybersecurity incident, exercise, or crisis. Its primary purpose is to conduct a comprehensive post-incident analysis that transforms the experience into actionable intelligence for continuous improvement. The report objectively reviews the entire event timeline—from initial detection through containment and recovery—identifying critical decision points, contributing factors, and the impact on systems and data.

The AAR systematically evaluates the effectiveness of the incident response team's actions, policies, and procedures against established protocols. It includes a thorough root cause analysis to uncover underlying vulnerabilities, systemic weaknesses, or operational gaps that facilitated the incident. Based on these findings, the report develops concrete recommendations for strengthening mitigation strategies, updating security controls, refining playbooks, and enhancing training programs. This document is essential for fostering a culture of learning and proactively improving an organization's cybersecurity posture against future threats.