Jan Marek

Background

About Jan Marek

My name is Jan Marek and I am the Co-Founder and Red Team Lead at Cyber Rangers, a cybersecurity firm specializing in advanced offensive security engagements, penetration testing and red team operations. I focus on deep technical offensive security research — particularly in Active Directory security, Windows OS internals, EDR/AV evasion, exploit development, and custom tooling — and I regularly work on complex real-world security assessments and adversary simulation exercises. I am passionate about continuously expanding my expertise in cybersecurity and sharing that knowledge with the community through talks, training, and practical tooling. My approach is hands-on, pragmatic, and rooted in understanding both attacker techniques and effective defensive strategies to help organizations strengthen their security posture. My life motto is “Failure isn't an option, it's a choice.” Specialties- Penetration Testing and Red Teaming (Windows, Active Directory)- Microsoft Security (Windows, Windows Server, Microsoft Sentinel)- Computer Forensics (Windows)- PowerShell - Microsoft Hyper-V Selected conferences where I delivered a talk- CYB3R Days - BSides Prague 2025 - Texas Cyber Summit 2022, 2023 - GoTech World 2024 - Qubit Conference - CIO Agenda - CQURE AWSC 2023, 2024 - Microsoft Ignite - TechEd - tietoEVRY Security Days - HackerFest - hacktivitycon - mayday.conf - HEK.SI - FreshIT - ShowIT