Senior Attack Engineer, External
Key Skills for This Role
Full Job Posting
What You’ll Do
- Design, build, and maintain highly scalable reconnaissance workflows that discover, enumerate, and fingerprint external-facing assets and services in production-grade Python.
- Research, explore, and parse large volumes of external-facing data, including unstructured and inconsistent sources, and turn it into accurate, actionable information.
- Develop robust approaches to data that is hard to reason about in code, such as free-form banners, web content, documents, and error output, and build parsing and enrichment that holds up across the long tail of real environments.
- Collect, store, and connect high volumes of information, and extend our attack-path modeling and graph data model to represent new identity, privilege, and relationship paths.
- Traverse identity relationships across the external surface, such as accounts, tenants, SSO and federation, exposed credentials, and third-party services, to find paths from exposure to compromise.
- Automate multi-step attack workflows that chain discovery, credential access, initial access, and post-exploitation into complete, safely proven attack paths.
- Research emerging external tradecraft and turn it into production attack content, with an emphasis on techniques that still succeed against hardened, well-monitored targets.
- Stand up and maintain representative test environments to validate, demonstrate, and regression-test attack scenarios.
- Build for production safety and scale: respect target and customer environments, rate limits, and scope while running across very large attack surfaces.
- Contribute to priorities and the coverage roadmap based on real customer environments, threat intelligence, and emerging techniques.
- Mentor teammates and proactively support their growth, and help define team standards for 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.
What You’ll Bring
- Deep, hands-on offensive experience against external attack surfaces, from reconnaissance through initial access and post-exploitation.
- 5+ years of hands-on experience in offensive security, security research, and/or security-focused software engineering, with recent work building and shipping offensive tooling.
- Demonstrated experience building reconnaissance and discovery systems that run at scale, not just one-off scripts.
- Strong skill at researching and parsing large amounts of messy, unstructured external data and turning it into usable, trustworthy information.
- Experience collecting, storing, and connecting high volumes of data, and reasoning about it as relationships, such as identities, assets, and trust.
- Command of identity-focused tradecraft: credential access, password and token attacks, SSO and federation weaknesses, and moving among identities, tenants, and services.
- Experience automating multi-step attack workflows end to end.
- Strong software engineering fundamentals with 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 build deep, practical expertise.
- Strong written and verbal communication, including clear technical documentation.
- A passion for building products, not just finding vulnerabilities.
- What Sets You Apart
- OSCP (or OSEP, CRTO, or equivalent offensive certifications).
- Experience with large-scale internet data sources and tooling, such as certificate transparency, passive DNS, and internet-wide scanning.
- Experience with cloud, SaaS, and hybrid identity attack surfaces (Entra ID, Okta, AWS, and similar), including on-prem to cloud pivots.
- Experience with external to internal pivoting and how perimeter footholds lead into additional access.
- Experience with graph databases and attack-path analysis, and with data lake or high-volume data storage and processing.
- Experience developing or contributing to offensive or recon tooling
- 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.
- Travel Required
- We are a fully remote company, and this job may require up to 5% of travel to be successful.
- Compensation and Values
- At Horizon3, we believe that our people are our greatest asset, and our compensation philosophy reflects this core value. We are committed to fostering an environment where all employees feel valued, respected, and rewarded for their contributions. Our compensation structure is designed to be fair, competitive, and transparent, ensuring that every team member is recognized and compensated equitably across roles, levels, and locations.
- Base salary range: $206,278 - $242,680 annually. The exact salary will be determined based on the selected candidate’s location, qualifications, experience, and relevant skills.
- Additional compensation: All full-time roles are eligible for an equity package in the form of stock options.
- Perks of Horizon3.ai
- Inclusive Team: We value diversity and promote an inclusive culture where everyone can thrive.
- Growth Opportunities: Be part of a dynamic and growing team with numerous career development opportunities.
- Innovative Culture: Work in a collaborative environment that encourages creativity and out-of-the-box thinking.
- Hybrid & Remote Work: We embrace a mix of remote and hybrid work models depending on role and location, including our Chicago office, where some roles require regular in-office presence.
- Competitive Compensation: We offer competitive salary, equity and benefits. Our benefits include health, vision & dental insurance for you and your family, a flexible vacation policy, and generous parental leave.
- You Belong Here
- Horizon3 is not just an equal opportunity employer - we are a community that values diversity, equity, and inclusion as fundamental principles of our culture and success. We are dedicated to fostering a workplace where everyone feels welcome and respected, regardless of race, color, religion, sex, national origin, age, disability, veteran status, sexual orientation, gender identity or expression, genetic information, marital status, hair length or any other legally protected status by law.
- Our commitment to diversity and inclusion means we strive to attract, develop, and retain a workforce that reflects the varied communities we serve. We believe that diverse perspectives drive innovation and strengthen our ability to create cutting-edge cybersecurity solutions. At Horizon3, every team member is valued and supported in an environment that encourages personal and professional growth.
- We welcome candidates from all backgrounds and experiences, and we encourage all qualified individuals to apply. Come be a part of Horizon3, where your unique contributions are recognized, and your potential is limitless.
- Other Duties
- Please note this job description is not designed to cover or contain a comprehensive listing of activities, duties or responsibilities that are required of the employee. Duties, responsibilities, and activities may change at any time with or without notice.
- Application Note
- In any materials you submit, you may redact or remove age-identifying information such as age, date of birth, or dates of school attendance or graduation. You will not be penalized for redacting or removing this information.
About Horizon3
Horizon3.ai is a private cybersecurity company providing organizations with continuous autonomous penetration testing.
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