Zach Ellerbrook

I do access control and personnel security administration for a 35 to 40 person Navy organization, inside a federal system governed by RMF. Two years of that work, about one of them formally designated.

On my own time I build security tools and write up what breaks along the way.

Right now that's ssh-detect-respond, a Python tool that follows SSH authentication logs and watches for brute-force attempts. It's finished as scoped, and its default threshold comes from replaying 34 days of real auth logs through it at 20 different settings. Including the setting that would have locked me out of my own server.

The writing is mostly about building technical things while deliberately working not to get dependent on the AI helping me build them.

• Access administration and personnel security for a 35 to 40 person organization at Navy Band Great Lakes, in an RMF-governed federal system.
• Secret clearance. Tier 3R investigation adjudicated January 2023, Continuous Evaluation since January 2025.
• Available from late February 2027 through SkillBridge.
• Navy career ends June 30, 2027.
• Chicago area after that.