Sean Metcalf
- Runs ADSecurity.org, a long-running reference for Active Directory attack and defense
- Founded Trimarc, a consultancy focused on Microsoft identity security reviews
- One of a small number of Microsoft Certified Masters in Directory Services
Bio
Sean Metcalf holds the Microsoft Certified Master certification in Directory Services, founded the consultancy Trimarc, and has published Active Directory and Entra ID security research at ADSecurity.org for over a decade, alongside talks at Black Hat, DEF CON, BSides, and DerbyCon.
Profile built from public research, conference, and company records.
Where their work shows up
ADSecurity.org is the closest thing the field has to a defender's manual for Active Directory: what attackers actually do, in order, and which configuration changes break each step. It is where the working guidance on tiered administration, privileged group hygiene, and delegation review was written down in a form an administrator could act on the same week. See the ITDR guide, password spraying, and the best ITDR for Active Directory ranking.
Related on Start with Identity
- PodcastSemperis
Semperis' biweekly show for defenders of hybrid Active Directory and Entra ID environments, hosted by 15-time Microsoft MVP Sean Deuby.
- PodcastEntra.Chat
A weekly show for Microsoft Entra administrators, with deployment stories from practitioners and the engineers who build the product. Hosted by a Microsoft empl
- GlossaryIdentity Resilience
The ability to keep authenticating and authorising legitimate users, and to recover the identity system itself, when the identity provider or directory is degra
- GlossaryKerberos
A ticket-based network authentication protocol using symmetric cryptography and a trusted third party, the Key Distribution Center. A client authenticates once,
- GlossaryLDAP
Lightweight Directory Access Protocol. A protocol for querying and modifying a hierarchical directory of entries, each identified by a distinguished name. Used
- ExpertCo-creator of BloodHound
Andy Robbins co-created BloodHound with Will Schroeder and Rohan Vazarkar, released at DEF CON 24, and led its extension from on-premises Active Directory into