Horizon3.ai · 5 hours ago
Senior Internal Red Team Engineer
United States
Full-time
Remote
Senior Level
$195K/yr - $242K/yr
5+ years expHorizon3.ai is a fast-growing, remote cybersecurity company dedicated to enabling organizations to proactively find, fix and verify exploitable attack vectors. They are seeking a highly experienced Senior Internal Red Team Engineer to emulate advanced adversaries, identify vulnerabilities, and enhance the company's security posture.
Artificial Intelligence (AI)Cyber SecurityEnterprise SoftwareMachine LearningNetwork Security
Responsibilities
Conduct comprehensive threat modeling and risk assessments to identify high-value targets, analyze potential attack vectors, and prioritize red team objectives
Design and execute end-to-end, objective-based red team operations targeting our production cloud and web environments, simulating real-world scenarios to test our defenses
Perform deep, security-focused source code reviews (primarily in Python and JavaScript) to identify complex vulnerabilities like logic flaws, injection, and RCE
Lead comprehensive security configuration audits of our AWS, Azure, GCP, Digital Ocean, and Kubernetes (K8s) environments, identifying exploitable misconfigurations, overly permissive IAM policies, and insecure network settings
Assess and test the security of our CI/CD pipelines (e.g., Jenkins, GitLab CI, GitHub Actions, ArgoCD, Crossplane, etc…) to identify attack paths, secret management flaws, and vulnerabilities that could lead to supply chain attacks
Conduct in-depth penetration tests against critical web applications, APIs, and cloud-native services
Actively collaborate with engineering and defensive teams (Blue Team) in purple team exercises to validate findings and improve detection and response capabilities in real-time. Perform retesting for validation of mitigations or remediations
Develop custom tooling, exploits, and automation scripts as required to bypass security controls. Develop and maintain red team methodologies, tools, and infrastructure
Stay abreast of the latest threat intelligence, vulnerabilities, and exploits; research and develop new exploitation techniques relevant to our technology stack
Investigate, own, and report on vulnerabilities, exploit paths, and their business impact. Author clear, detailed reports and present findings to both technical and leadership audiences
Qualification
Required
5+ years of hands-on experience in offensive security, with a demonstrable track record of leading complex web application and cloud penetration tests
Proven ability to read, review, and identify vulnerabilities in source code (especially Python and JavaScript)
Deep, practical experience attacking and auditing cloud environments (eg: AWS, GCP, Azure) environments (e.g., S3, EC2, RDS, IAM, Lambda, Azure Blob Storage, Google Cloud Storage, etc...) and Kubernetes clusters
Must hold one or more advanced, industry-recognized offensive security certifications: OSCP, OSWE, OSCE, CRTO, or GIAC (GCPN, GXPN)
Expert-level knowledge of modern web application security, including the OWASP Top 10, API security, and common framework vulnerabilities
Strong proficiency in common offensive security tools (e.g., Burp Suite, Nmap) and C2 frameworks (e.g., Cobalt Strike, Sliver, Brute Ratel)
Strong written and verbal communication, including technical documentation and the ability to explain technology to non-technical audiences
Preferred
Experience in a blue team, incident response, or system administration role
Experience with other cloud providers (e.g., GCP, Azure)
Experience with OSINT, phishing, and social engineering campaigns
Familiarity with WAF technologies (e.g., AWS WAF, Akamai)
Relevant cloud or K8s certifications (e.g., AWS Certified Security - Specialty, Certified Kubernetes Administrator (CKA))
Benefits
Health, vision & dental insurance for you and your family
Flexible vacation policy
Generous parental leave
Company
Horizon3.ai
Horizon3.ai offers an autonomous penetration testing platform that helps organizations proactively find and fix security vulnerabilities.
201-500 employees
Funding
Current Stage
Late StageTotal Funding
$178.5MKey Investors
Prosperity7 VenturesNew Enterprise AssociatesCraft Ventures
2026-01-13Series Unknown
2025-05-22Series D· $100M
2023-08-08Series C· $40M
Leadership Team
Snehal Antani
Co-Founder & CEO
Holly Grey
Chief Financial Officer
Recent News
2025-12-16
Company data provided by crunchbase