Prusec helps security leaders in financial services, insurance, and industry stress-test their ransomware readiness, sharpen crisis response, and build Security Operations teams that perform under pressure.
We stress-test whether your detection, containment, and response capabilities hold under real attack conditions. Starting point is a tailored tabletop exercise built around your environment, threat profile, and maturity level — surfacing the gaps that documentation doesn’t show.
Structured crisis simulations calibrated to your organisation. We test not just your playbooks, but the human factors: decision-making under pressure, escalation ownership, and cross-team coordination when it counts. These sessions frequently become the foundation for deeper engagements.
We design, build, and mature Security Operations functions that work for your organisation’s size, threat profile, and culture. Where needed, we step in as interim security lead while you hire, restructure, or recover from an incident.
Prusec takes its name from the prusik, a mountaineering technique that every serious climber knows. A prusik knot moves freely under normal conditions. Under sudden load, it locks. It holds the climber’s weight when the rope goes taut. It is the difference between a controlled descent and a fall.
Security works the same way. Processes and teams that function smoothly day-to-day need to hold firm when pressure spikes suddenly, whether that is a ransomware trigger at 2am, a containment decision under incomplete information, or a board call in the middle of an active incident. That is the capability Prusec is built to develop.
The logo reflects this directly. It is a stylised representation of the prusik knot itself, the geometry of tension, friction, and hold rendered as a mark. Simple under normal observation. Engineered to grip when it matters.
Mark Beerends spent over a decade leading Security Operations at two of Europe’s largest financial institutions, including as Executive Director and global Head of SOC at UBS. He has built and run cyber security programs at global scale, managing the full range of technical and organisational complexity that comes with tier-one financial services environments.
That operational background is the foundation of Prusec’s work. Mark brings it directly into client engagements, whether stress-testing ransomware response capabilities, running crisis simulations with leadership teams, or designing SOC functions that hold up under real conditions. He knows what breaks under pressure because he has been the person responsible when it did.
Technical excellence, curiosity, and a pragmatic mindset are the key aspects that Guillaume believes are essential to strengthen an organisation’s cyber resilience.
Guillaume has gained extensive hands-on experience in offensive security, with a strong background in penetration testing and red teaming across various industries. As a CREST Registered Penetration Tester holding OSCP and OSWP certifications, he combines deep technical skill with a structured approach to assessing and improving security postures.
At Prusec, Guillaume supports our clients by identifying vulnerabilities before attackers do — translating complex technical findings into clear, actionable improvements.
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