Why I believe cyber resilience must be tested — and why Rempar25 is an opportunity not to be missed

There is one simple conclusion I have drawn from my years in the field: no organisation is truly ready until it has tested its ability to respond to a real crisis. Not a paper-based scenario. Not a committee meeting. A real stress test, with uncertainty, decision-making under pressure, teams that must coordinate, and impacts that go beyond the boundaries of the IT department.

And that is exactly why the ANSSI’s Rempar25 initiative seems extremely relevant and necessary to me.

A rare opportunity to face a realistic scenario

Rempar25 is more than a simple exercise: it is an immersive experience, a full-scale training exercise built around a plausible and remarkably effective scenario — a digital blackout caused by the compromise of a critical supplier. And we all know how interdependencies with our service providers can become a weak point.

This type of exercise makes it possible to test not only the tools, but above all the human and organisational dynamics: coordination between IT and business teams, crisis communication, real-time decisions, business continuity under degraded conditions…

Why take part? The benefits are numerous:

• Test your measures in near-real conditions Far from a simple audit, Rempar25 immerses teams in a crisis context where decisions must be made quickly, with incomplete information, as in real life.
• Strengthen coordination between IT, business teams and service providers A crisis is not managed solely within IT departments: business functions, executive management, external partners… all must be integrated into the thinking and the response.
• Improve crisis communication Knowing how to communicate effectively — internally as well as externally — is a major challenge in the event of a cyberattack. Rempar25 allows you to put your communication strategies to the test.
• Prepare for business continuity without nominal IT What should you do if your usual tools are unavailable? The exercise encourages the development of resilient solutions and a rethink of certain key processes.

If you are a CISO, cybersecurity expert, infrastructure manager, or even a business manager with a focus on risk management: register your organisation for Rempar25. It is an opportunity to face the unexpected in a secure, structured setting, enriched by the diversity of participants.

You do not need to be a multinational to take part. The exercise is designed to adapt to the maturity of each organisation. And the last day to register is 20 April 2025. Now is the time to act.

? Registration link and practical information — ANSSI website