4 lessons

Detection & Response

Prevention fails. Telemetry → detection → alert → investigation → containment → recovery → learning, plus vulnerability management that prioritises exposure over CVSS.

Asset→Threat→Attack Surface→Trust Boundary→Vulnerability→Exploit Path→Impact→Mitigation→Defense in Depth→Residual Risk

Every lesson below identifies the asset, attacker capability and boundary before naming the vulnerability. Controls are split into prevention, detection and recovery; residual risk is explicit.