Staff Defensive Security Software Engineer

Horizon3.ai is an innovative cybersecurity company focused on helping organizations identify and fix vulnerabilities. They are seeking a Staff Defensive Security Software Engineer to join their Detection & Deception Team, focusing on enhancing Tripwires, a threat detection capability within their NodeZero platform.

Responsibilities:

• Owns the end-to-end technical vision for the workstream and rallies the team around it — from blank doc through shipping, iterating, and deprecating
• Production code contributions at Lead/Staff level in a modern backend language (Go, Rust, Python, or similar) in a service-oriented environment
• The ability to work independently with minimal supervision, demonstrating initiative and a high level of energy
• Work closely with other cross-functional partners to build and improve our product portfolio
• Strong technical writing and documentation skills, with the ability to convey findings and methodologies to both technical and non-technical stakeholders
• Proficiency in designing, presenting, and evaluating technical solutions, ensuring high-quality software and secure development practices
• Sets and raises the technical bar (design reviews, code quality, operational discipline) by example rather than by mandate
• Mentors and enhances the engineers around them; Build the frameworks and architecture for others to do the best work of their careers
• Holds the team accountable to outcomes rather than activity; surfaces risks and tradeoffs early and in writing
• Translates ambiguous product goals into concrete technical roadmaps
• Partners closely with PM — comfortable in PRD reviews, not just sprint planning
• Sequences an MVP without painting the team into a corner

Requirements:

• Python: Expert-level proficiency in large-scale Python software development
• Network Security: Deep experience with network security topics such as reconnaissance and lateral movement
• Windows Experience: Proficiency with Active Directory, Windows authentication, and other windows internals
• Network Protocols: Strong understanding of network protocols such as SMB and WMI and their intricacies, including their role in exploitation vectors
• Database Experience: Experience with relational (Postgres) or graph (Neo4j) database systems
• Security Experience: Minimum of 4 years of experience in building offensive or defensive security solutions, ideally in endpoint, threat detection, or low-level systems
• Education: Bachelor's Degree in Computer Science, Computer Engineering or related field. Equivalent experience may be considered if demonstrable through proof-of-concept write-ups, published vulnerability research, or similar achievements
• OSCP (Offensive Security Certified Professional), GCWN (GIAC Certified Windows Security Administrator) or equivalent certifications
• Previous experience in red teaming or penetration testing, incident response, detection engineering, deception technologies, or other deeply technical roles with relevant skill sets
• Previous experience working on large-scale software projects
• Experience administering, attacking, or defending cloud environments
• Knowledge of and experience with Docker and containerization technologies
• Familiarity with identity and directory services such as Active Directory, Entra ID, or Okta
• Familiarity with cloud authentication and authorization technologies such as Azure Service Principals or AWS IAM