Staff Attack Engineer, Internal/AD

Horizon3

10d•$247,000 - $275,000•Remote

About The Position

Horizon3 is a fast-growing, remote cybersecurity company dedicated to the mission of enabling organizations to proactively find and fix and verify exploitable attack vectors before criminals exploit them. Our flagship product, the NodeZeroTM platform, delivers production-safe autonomous pentests and other key assessment operations that scale across the largest internal, external, cloud, and hybrid cloud environments. NodeZero has been adopted by organizations of all sizes, from small educational institutions to government agencies and Global 100 enterprises. It is used by ITOps/SecOps teams, consulting pentesters, and MSSPs and MSPs. We are a fusion of former U.S. Special Operations cyber operators, startup engineers, and formerly frustrated cybersecurity practitioners. We're committed to helping solve our common security problems: ineffective security tools, false positives resulting in alert fatigue, blind spots, "checkbox" security culture, cybersecurity skills shortage, and the long lead time and expense of hiring outside consultants. Collectively, we are a team of learn it alls, committed to a culture of respect, collaboration, ownership, and results.

Requirements

Deep, hands-on offensive experience against Active Directory and internal enterprise networks, from initial foothold through domain and enterprise compromise.
Command of current AD tradecraft: credential access, Kerberos attacks, NTLM coercion and relay, AD Certificate Services abuse, ACL and GPO abuse, and lateral movement and persistence.
Demonstrated experience attacking modern, hardened environments (NTLM deprecation and enforced signing, Kerberos-only, tiered administration).
Strong software engineering fundamentals with expert-level Python, and a track record of shipping and maintaining production-quality code, not just scripts and proofs of concept.
Ability to independently research unfamiliar systems and technologies and rapidly become the team's expert.
A track record of technical leadership: setting direction, driving high-complexity and high-risk work, and mentoring other engineers.
Strong written and verbal communication, including clear technical documentation.
A passion for building products, not just finding vulnerabilities.
8+ years of combined offensive security and/or software engineering experience, with significant time focused on Active Directory and internal network attacks.

Nice To Haves

OSCP (or OSEP, CRTO, or equivalent offensive certifications).
Experience with SCCM, Windows Admin Center, and other modern Windows management-plane attack surfaces.
Experience with hybrid identity attacks (Entra ID and Entra Connect, primary refresh tokens, seamless SSO) and on-prem to cloud pivots.
Experience developing or contributing to offensive tooling like BloodHound, Impacket, netexec, etc.
Familiarity with graph databases (Neo4j) and attack-path analysis.
Experience integrating security research into production, multi-tenant SaaS.
Public contributions to the field: open-source tools, technical blog posts, conference talks, or published CVEs.
Experience building production-safe autonomous or automated offensive tooling.

Responsibilities

Serve as the technical lead and primary subject matter expert for internal-network and Active Directory attack capabilities across NodeZero.
Research emerging AD and internal tradecraft (AD Certificate Services abuse, SCCM/ConfigMgr and other management-plane attacks, Kerberos abuse and delegation including RBCD, NTLM and Kerberos coercion and relay, shadow credentials, ACL and GPO abuse, and hybrid identity pivots) and turn it into production attack content.
Design, build, and maintain production-grade Python that powers these capabilities safely and at enterprise scale.
Focus on modern, hardened environments (NTLM deprecation and SMB signing by default, Kerberos-only, Protected Users and tiered admin, LAPS and gMSA/dMSA) and build attacks that still succeed when the easy paths are closed.
Stand up, configure, and exploit representative AD test environments to validate, demonstrate, and regression-test attack scenarios.
Extend our attack-path modeling and graph data model to represent new identity, privilege-escalation, and lateral-movement paths.
Set priorities and the coverage roadmap based on real customer environments, threat intelligence, and emerging techniques.
Mentor and level up attack engineers, and raise the bar on code quality, research rigor, and operational safety.
Collaborate cross-functionally with engineers, product managers, and customer-facing teams, and author internal documentation and external research and blog posts.