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.

The information and views presented here are my own and do not reflect the official position of any employer or organization.

Here are some of my professional certifications:

During the past years, I had the honor to speak at these amazing conferences and events:

• 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

If you are interested in having me speak at your conference or event, please message me on LinkedIn.