“The Day Before the Breach” – A Cyber-Stress Test Awakening at MedData Grid
Karin had a habit of asking dangerous questions.
It was a rainy Monday in Brussels when she looked across the conference room table and dropped one:
“We’ve got policies, procedures, and risk registers… but what happens when the lights actually flicker?”
As the Chief Information Security Officer of MedData Grid, Belgium’s national health records platform—and now an NIS2 essential entity—Lotte had seen enough boardroom slide decks. What worried her was that everything looked tidy on paper, but nothing had ever been truly tried.
That’s when she printed off a copy of ENISA’s new Cyber-Stress Test Handbook, circled a sentence in red ink, and pinned it to the SOC bulletin board:
“Cyber stress testing demonstrates an organisation’s ability to withstand and recover from significant cyber incidents while continuing to deliver critical functions.”
Day 1 – The Tiger Team
Within a week, Lotte formed her “Tiger Team”:
- Jens, who ran the 24/7 SOC and was famous for two things: sarcasm and Sysmon.
- Farah, the steady hand behind their business continuity planning.
- Tom, a cloud engineer who had a dashboard for everything—except human behaviour.
- Sofie, procurement lead with a post-it wall of third-party risk.
- And Anne, the internal auditor with a memory like a vault.
Their mission: Run a cyber stress test in 60 days, using ENISA’s playbook and the 102 CyFun Essential controls.
“Let’s not wait for the regulator,” Lotte said. “Let’s simulate our worst day now—while it’s still our choice.”
Day 10 – What Could Go Wrong?
They gathered in a room with whiteboards and strong coffee. Farah posed the question:
“What keeps you up at night?”
Jens didn’t blink. “Mass ransomware. Gets in through a supplier tool, triggers before we detect. Locks patient portals, logs are corrupted. You want pressure? That’s it.”
They chose two scenarios:
- Ransomware in the public-facing application cluster
- Cloud outage in EU-West with vendor silence for 6 hours
Each one mapped directly to CyFun controls like:
- PR.IP-4 – Are backups tested?
- RS.RP-1 – Can we execute the response plan?
- ID.SC-4 – Do we actually vet the failover processes of our suppliers?
Day 30 – The “Crash Day”
Instead of blinking lights and spinning fans, their test was quiet. Controlled. Each department worked through a questionnaire simulation:
- Jens traced detection-to-response time: 22 minutes—but their SIEM never flagged lateral movement.
- Tom tried triggering their failover. “Only half the configs replicated,” he admitted. “We never tested the subnet ACLs in secondary.”
- Sofie reviewed contracts: “We have SLAs. But no RTOs. And zero logs on their last DR drill.”
Anne captured every step. Not just what failed—but why, and what it would’ve cost.
Day 50 – The Story They Weren’t Ready For
The audit findings weren’t about blame. They were about readiness.
- ✅ Access Control (PR.AC-4) – worked as designed. Privileges were cut in real time.
- ⚠️ Backup and Recovery (PR.IP-4) – backups existed, but restoration time was 6× the goal.
- ❌ Supplier Risk (ID.SC-3, ID.SC-4) – No proof vendors could isolate workloads during a failover.
Anne compiled the results. She aligned each one with the relevant CyFun control, ISO/IEC 27001 clause, and NIS2 Article 21 theme. She color-coded them by residual risk, and drafted the Management Action Plan.
Day 60 – From Simulation to Reality
The day the board reviewed the results, they didn’t flinch.
They nodded.
For the first time, resilience had moved from theory to muscle memory.
The regulator hadn’t knocked yet—but when they did, MedData Grid would be ready.
Lotte smiled, finally satisfied.
“Now we know how the engine runs… not just how it looks on paper.”
🛠️ Key Takeaways
- Stress tests = living evidence of your ISO 27001 controls in action.
- CyFun Essentials give structure; ENISA’s handbook brings scenario realism.
- For NIS2 compliance, proving control effectiveness beats documenting it every time.
Want to prepare your own “worst plausible day”? Start with the handbook. End with confidence.
1 Why pay attention?
ENISA’s Handbook for Cyber Stress Tests positions stress testing as a light-weight, scenario-based assessment that lets operators prove they can “withstand and recover from significant cybersecurity incidents” while continuing to deliver critical services . Under NIS2 Article 21 every important and essential entity must show “appropriate and proportionate” technical/organisational measures and be able to demonstrate them to regulators. Stress testing provides exactly that evidence:
Download your copy: LINK
- Targeted & metrics-driven – focus on a small set of high-impact scenarios with concrete resilience metrics such as time-to-detect and time-to-recover .
- Lightweight & independent – desktop questionnaires and data reviews minimise disruption and cost .
- Dialogue-friendly – results spark constructive follow-up instead of one-off compliance box-ticking .
2 Where the handbook meets NIS2 controls
| NIS2 risk-management theme (Art 21 §2) | Stress-test focus area | Example ISO/IEC 27001:2022 Annex A controls |
|---|---|---|
| Incident handling & crisis mgmt | Scenario execution; measurement of detection/response KPIs (Steps 3-4) | A.5.24 – A.5.27 |
| Business continuity & recovery | Recovery metrics (RTO/RPO) and fail-over tests | A.5.29, A.8.13 |
| Vulnerability & patch management | Preparedness questions on patch windows and compensating controls | A.8.8 |
| Supply-chain security | Identification of single points-of-failure and shared providers | A.5.19 – A.5.23 |
| Testing & auditing | The entire five-step loop (scope → design → execute → analyse → follow-up) | A.5.36 |
| Risk analysis & policies | Pre-test definition of critical scenarios and assets | A.6.1, A.5.12 |
Tip: If you are already ISO 27001-certified, map each handbook step to your Statement of Applicability to show how existing controls underpin the test evidence.
3 How to adopt – a 90-day roadmap
| Timeline | Action | Output / value |
|---|---|---|
| Days 1-15 | Assemble a stress-test squad (CISO, BCM lead, SOC manager, vendor mgmt). Adopt the handbook’s five-step template . | Project charter & scope aligned to NIS2 risk areas. |
| Days 16-45 | Design scenarios – pick 2-3 “severe-but-plausible” risks (e.g., mass ransomware, cloud outage). Define metrics (MTTD/MTTR, RTO). | Approved questionnaire & evidence list. |
| Days 46-60 | Execute desktop test – each domain owner completes the workbook; validate with spot-interviews/log extracts. | Raw scores + evidence folder. |
| Days 61-75 | Analyse & gap-rank – aggregate scores, highlight systemic supply-chain exposures . | Heat-map & action register. |
| Days 76-90 | Report & commit – brief execs and, if required, the national CSIRT/authority; link actions to ISO control owners. | Board-level report that doubles as NIS2 evidence. |
4 Leveraging the CyFun Essentials control set
If you already track the 102 CyFun Essential controls, stress tests give immediate coverage to Key Measures such as:
- ID.AM-1 – inventory accuracy is verified when scenarios target unknown assets.
- PR.AC-1 – response metrics expose gaps in privileged-access revocation.
- DE.CM-1 – time-to-detect becomes a live KPI.
- RS.RP-1 / RC.RP-1 – playbooks are stress-tried, not shelf-ware.
Link your stress-test findings back to each CyFun control to keep your gap register and NIS2 evidence chain in one place.
5 Bottom line
Cyber stress testing converts NIS2’s broad “appropriate measures” mandate into a repeatable drill that demonstrates real-world resilience. ISO 27001-certified companies already hold 80 % of the required controls; the handbook shows how to prove they work under pressure. Early movers will face audits with confidence—and likely gain a competitive edge when customers ask for proof of NIS2 readiness.
Ready to start? Grab ENISA’s template, pick your worst-plausible day, and run the numbers before the regulator does.
