Trimarcisia, "feat of three horsemen", was an ancient Celtic military cavalry tactic where there was always a rider ready to mount the horse of a fallen soldier.

Trimarc Security, LLC ("Trimarc") is a professional services company based out of Washington, DC that helps organizations secure their Microsoft platform, both on-premises and in the cloud. We focus on a “reality-based security model” which targets attacker tactics and how to stop them. Our methodology identifies security issues in an organization attackers could exploit to fully compromise the environment and provide custom recommendations to effectively mitigate these issues.

Trimarc works on continuously developing defensive strategies to combat evolving attack techniques. We focus on defensive layers within the enterprise – while any single defense may fail, there are others that compensate for this and provide additional detection and/or mitigation for that area.

Our Founder Sean Metcalf

Trimarc’s technical expertise group is headed by our Chief Technology Officer, Sean Metcalf. Sean is one of about 100 Microsoft Certified Masters (MCMs) in Directory Services in the world. He runs, a Microsoft-focused enterprise security blog focused on explaining how current attacks work and how to detect, mitigate, and prevent them. He performs security research focused on the Microsoft platform and has identified interesting Kerberos behavior as well as other unique research. You can view his conference talk slides & videos in our presentations section.

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