Developing severe but plausible scenarios means anchoring worst-case impact in real, demonstrable threat intelligence — actual TTPs relevant to your sector — layered into a scenario that plausibly cascades into outcomes that would truly hurt: loss of critical services, systemic contagion, or breach of regulatory thresholds.
Severity is tested against your real crown-jewel assets, while plausibility comes from grounding each step in techniques observed in the wild, consistent with TIBER-EU and TLPT principles.
This is the foundation on which response and recovery plans should be built or adjusted, and subsequently tested.
