SummaryWe are hiring a Staff Attack Engineer to join the team behind our Rapid Response product. You will research and productize real-world exploitation techniques so customers can quickly understand whether newly disclosed or actively exploited vulnerabilities affect their environments-and what an attacker could do next.
You will focus on high-consequence vulnerabilities that are actively exploited, newly disclosed, or likely to generate significant attention - from CISA Known Exploited Vulnerabilities (KEVs) and Zero-Days to N-Days and emerging attack techniques. You will turn vulnerability research and attacker tradecraft into safe, repeatable, automated attack capabilities for the issues that are in the news, creating urgent customer concern, or most likely to affect the broader security community. This is not a traditional consulting or manual-pentesting role. Your work will help
security teams rapidly validate exposure, prioritize remediation, and verify that defenses are working.
What You'll Do- Research and reproduce high-consequence vulnerabilities across enterprise networks, applications, identity systems, cloud environments, and infrastructure-including CISA KEVs, CVEs, N-Days, and Zero-Days.
- Study attacker tactics, techniques, procedures, and campaigns observed in the wild, including tradecraft not tied to a single CVE.
- Turn vulnerability research and real-world attacker behavior into safe, repeatable proof-of-exploit capabilities, attack paths, and automated modules for Rapid Response and NodeZero.
- Demonstrate realistic impact-including privilege escalation, credential access, lateral movement, persistence, and data access-without unnecessary disruption.
- Validate remediation and containment by safely retesting vulnerabilities and security controls.
- Improve execution speed, reliability, observability, and evidence quality while collaborating with research, product, and engineering teams.
What You Bring- Strong Python and software engineering skills, including experience building, testing, and operating production-quality tooling.
- Solid penetration testing, vulnerability research, and exploit-development fundamentals.
- Hands-on experience with enterprise networks, applications, identity systems, cloud environments, or endpoint security.
- Demonstrated ability to reproduce vulnerabilities and convert manual techniques into reliable automation.
- Understanding of common attack chains, trust boundaries, authentication and authorization, privilege escalation, and lateral movement.
- Ability to balance speed, safety, reliability, coverage, and actionable evidence.
- Curiosity about how attackers exploit newly disclosed vulnerabilities and how defenders can validate exposure quickly.
- Strong ownership, judgment, and communication skills in ambiguous or time-sensitive situations.
Nice to Have- Experience with CISA KEVs, CVE analysis, N-Day research, Zero-Day research, or responsible disclosure.
- Background in incident response, threat hunting, purple teaming, or security operations.
- Experience with AWS, Azure, GCP, Kubernetes, Active Directory, Entra ID, Okta, or hybrid environments.
- Experience with exploit development, reverse engineering, malware analysis, or vulnerability research.
- Contributions to security research, CVEs, conference talks, open-source tools, or technical publications.
- CTF experience or equivalent hands-on offensive security practice.
- Bachelor's Degree in Computer Science, Computer Engineering or related field.
- OSCP (Offensive Security Certified Professional) or equivalent certifications.
Travel RequiredWe are a fully remote company, and this job may require up to
10% of travel to be successful.
Perks of Horizon3- 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.
Compensation and ValuesAt 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: $230,000 - $275,000 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.
Other DutiesPlease 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 NoteIn 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.
