Senior/Staff Attack Engineer, Rapid Response

Get to Know Us 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.   SUMMARY We 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 balanc