David Horák is a System Security Engineer and Team Leader with 9+ years of experience securing Windows infrastructures and Active Directory. He has delivered 35+ security assessments across SMB, enterprise, and critical infrastructure, giving him a strong perspective on what security looks like in real environments - not just in theory. His work focuses on practical hardening, attack surface reduction, and building security baselines that organizations can actually implement.

David is also the founder of Horizon Secured, where he shares practical, defender-focused resources for Windows and AD security in the form of articles, tools, guides, and training. The goal is simple: reduce the noise and help administrators and defenders implement best practices the right way.

He regularly teaches and develops courses focused on Windows infrastructure security and building secure Active Directory environments. His contributions to the community helped him earn the Microsoft Most Valuable Professional (MVP) award.