Lector

Meet Your Instructor: David Horák

• Founder, Horizon Secured • Cybersecurity Engineer & Team Lead at ALEF • Microsoft MVP

With 8+ years securing Windows & Active Directory and 30+ security assessments delivered across SMB, enterprise, and critical infrastructure, I focus on turning complex security into clear, practical steps—so you can harden production environments with confidence.

My Journey into Cybersecurity

I started as a Windows Server Administrator. When I moved into security, I discovered there was no single, practical path for Windows Infrastructure Security—you had to stitch together bits from courses, blogs, and talks. That experience shaped my approach.
To help others avoid that noise, I founded Horizon Secured and created a structured path to learn, build, and defend Windows/AD the right way.

What I Do Today

Lead a consulting team at ALEF that helps customers assess, secure, and improve Windows/AD (from baselines and hardening to remediation and recovery planning).

Build practical training: Windows Infrastructure Security (deep-dive) and Building a Secure Active Directory (hands-on, step-by-step).

Publish free resources—step-by-step guides and the ADProbe Active Directory misconfiguration scanner—to accelerate real-world hardening.

Certifications & Expertise

• Certified by Microsoft, GIAC, EC-Council, and CompTIA
• Specializing in Windows Security, Active Directory Hardening, Attack & Defense Strategies
• Passionate about teaching cybersecurity in a practical, no-fluff way