BrettĀ Fitzpatrick
Lead Security Engineer at Klaviyo
Boston, Massachusetts, United States
Summary
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Seniorš
Top SchoolBrett Fitzpatrick is a Lead Security Engineer based in Boston with 8 years of hands-on experience building proactive threat intelligence, hunting, and detection platforms for both startups and enterprise teams. At Klaviyo he leads threat intel and hunt efforts, pairing reactive investigations with proactive enrichment pipelines and OpenCTI/Elastic integrations. Previously he architected serverless enrichment services and drove ECS/ECS schema contributions to better represent cyber observables at petabyte scale, and holds an inventor credit for distributed network-scanning C2 detection. Skilled in Python and Go, cloud-native stacks (AWS, Lambda, ECS/Fargate), SIEMs (Splunk, Elastic), and schema work (ECS, STIX, SIGMA), he blends engineering rigor with operational threat hunting. Collected experience across product-facing architecture and CyOC operations means he designs defensible data flows that are both auditable and operationally effective.
8 years of coding experience
5 years of employment as a software developer
Bachelor of Science (BS) Computing Security, Bachelor of Science (BS) Computing Security at Rochester Institute of TechnologyHigh School Diploma, High School Diploma at New Paltz High School
Stackoverflow
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Github Skills (38)
opencti10
cybersecurity10
security10
cobalt10
threat-intelligence10
mitre-attack9
search-engine9
java9
threat-hunting9
cyber-threat-intelligence9
rest9
elastic-apm9
elasticsearch9
elastic8
django8
Programming languages (6)
Github contributions (5)
brett-fitz/proactiveti
Oct 2023 - Dec 2025
All things Proactive Threat Intelligence (PTI). My notes, findings, techniques and ramblings.
Contributions:15 reviews, 24 PRs, 39 pushes in 2 years 2 months
threat-intelligence
brett-fitz/pyMalleableProfileParser
Sep 2021 - Nov 2022
Parses Cobalt Strike malleable C2 profiles.
Contributions:4 releases, 8 reviews, 40 commits in 1 year 2 months
c2-profilescobalt-strikecobaltstrike
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