Senior Attack Engineer, Offensive Tooling

Get to Know Us Horizon3.ai 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.   SUMMARY We are looking for an Offensive Tooling Engineer to design, develop, and maintain a custom implant framework and supporting C2 infrastructure. You will build cross-platform post-exploitation capabilities in Rust, develop evasion techniques, and create tooling that operates reliably in defended environments. This is a hands-on engineering role — you will own the full lifecycle from concept through deployment, testing, and monitoring. Your work will have a significant impact on the effectiveness of the NodeZero proactive security platform towards helping defenders prepare themselves against real world threats. ESSENTIAL FUNCTIONS - Develop and maintain a multi-platform implant written in Rust (Windows, Linux, macOS; x86/x64/ARM) - Build and extend C2 server infrastructure, task dispatch, and communications protocols - Implement post-exploitation modules: credential access, process injection, privilege escalation, lateral movement - Research and implement AV/EDR evasion techniques to keep tooling operational against modern defenses - Design and build network pivoting and tunneling capabilities - Write integration tests that exercise tooling against real targets across multiple OS and architecture combinations COMPETENCIES/REQUIREMENTS - Strong proficiency in Rust, including unsafe code, FFI, async runtimes (tokio), and cross-compilation - Deep knowledge of Windows internals: Win32 API, process injection, memory manipulation, DLL loading, PE format - Experience with credential access techniques (DPAPI, LSASS, browser credential stores) - Familiarity with Linux internals: libc, process enumeration - Understanding of networking at the packet level (TCP/IP, ICMP, custom binary protocols) - Demonstrated experience building or maintaining C2 / implant software (custom or open-source) - Background in red team operations or offensive tool development - Proficiency in Python for developing and maintaining attack automation and integration - Experience developing production safe, high quality code deployed to end user machines DESIRED/NICE TO HAVE - Experience with privilege escalation technique development - Experience researching and implementing EDR evasion techniques - PE parsing and reflective loading - Integration testing offensive tools against defended environments   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. - Remote Work: We are a 100% remote company. Enjoy the convenience and work-life balance that comes with remote work.  - 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. 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. In accordance with various State’s transparency regulations, we provide the following salary range information for this position: - Base salary range: $180,000 - $240,000 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. 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, 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.