Security Detection Engineer III

At F5, we strive to bring a better digital world to life. Our teams empower organizations across the globe to create, secure, and run applications that enhance how we experience our evolving digital world. We are passionate about cybersecurity, from protecting consumers from fraud to enabling companies to focus on innovation. Everything we do centers around people. That means we obsess over how to make the lives of our customers, and their customers, better. And it means we prioritize a diverse F5 community where each individual can thrive. The Security Engineer III, Detection Engineering is a career-level security engineering professional responsible for developing, testing, deploying, and continuously improving detection capabilities that support Security Operations. As part of the Security Operations Platform Engineering (SOPE) team, this role focuses on transforming threat intelligence, telemetry, and security requirements into reliable, actionable detections that improve visibility and reduce organizational risk. The engineer partners closely with Incident Response, Threat Intelligence, Logging Engineering, and platform engineering teams to build scalable, threat-driven detection capabilities while advancing automation, detection coverage, and operational maturity. Primary Responsibilities • Develop and maintain custom detections using Detection-as-Code practices, including version control, peer review, testing, and CI/CD deployment workflows. • Analyze and improve detection coverage by mapping telemetry and detections to adversary behaviors and the MITRE ATT&CK framework, identifying gaps and prioritizing enhancements. • Partner with Incident Response, Threat Intelligence, Logging Engineering, and security platform teams to translate emerging threats, investigations, and telemetry into actionable detection content. • Validate and tune detections through adversary emulation, atomic testing, purple-team exercises, and production feedback to improve signal quality and reduce false positives. • Automate and optimize detection engineering workflows, alert enrichment processes, and operational activities to improve efficiency and scalability. • Support onboarding of new log sources and security telemetry by collaborating with engineering and infrastructure teams to establish detection coverage across new environments and technologies. • Create and maintain detection documentation, runbooks, coverage assessments, and technical standards while participating in an engineering on-call rotation. • Help define detection strategy for AI and agentic systems (prompt injection, tool and function abuse, agent identity and credential misuse, data exfiltration via model outputs), and explore using AI to accelerate detection engineering workflows.Required Skills / Qualifications • Bachelor's degree in Information Security, Computer Science, Engineering, or related field, or equivalent practical experience. • 5+ years of experience in cybersecurity, security engineering, detection engineering, security operations, threat hunting, or a related discipline. • Experience developing, tuning, or maintaining detections within a SIEM, EDR, log analytics, or security monitoring platform. • Experience with scripting, automation, or data analysis using Python, PowerShell, SQL, KQL, SPL, or similar technologies. • Strong understanding of attacker techniques, detection methodologies, and frameworks such as MITRE ATT&CK. • Strong analytical, problem-solving, communication, and cross-functional collaboration skills. Preferred Skills / Qualifications • Experience implementing Detection-as-Code practices, including Git-based workflows, automated testing, and CI/CD pipelines. • Experience with adversary emulation, atomic testing, purple-team exercises, or detection validation frameworks. • Experience performing detection coverage analysis and developing ATT&CK-based coverage roadmaps. • Experience onboarding log sources and building detections across cloud, endpoint, network, identity, or SaaS environments. • Experience with platforms such as CrowdStrike, Splunk, Microsoft Sentinel, Chronicle, Elastic, or similar security technologies. • Familiarity with AI/LLM threat models (prompt injection, tool and function abuse, agent identity and credential misuse, data exfiltration via model outputs) or frameworks such as MITRE ATLAS and the OWASP LLM Top 10 — and interest in applying AI to accelerate detection engineering workflows.Work Environment This is a full-time engineering role and is not a shift-based position. Participation in an engineering on-call rotation is required and may occasionally require support outside normal business hours during critical incidents, platform outages, or detection-related operational events. The Security Engineer III may be engaged as a subject matter expert during security incidents but is not responsible for primary incident response or SOC operations. Travel may be required up to 5%, including occasional international travel. #LI-SS5 The Job Description is intended to be a general representation of the responsibilities and requirements of the job. However, the description may not be all-inclusive, and responsibilities and requirements are subject to change. Please note that F5 only contacts candidates through F5 email address (ending with @f5.com) or auto email notification from Workday (ending with f5.com or @myworkday.com). Equal Employment Opportunity It is the policy of F5 to provide equal employment opportunities to all employees and employment applicants without regard to unlawful considerations of race, religion, color, national origin, sex, sexual orientation, gender identity or expression, age, sensory, physical, or mental disability, marital status, veteran or military status, genetic information, or any other classification protected by applicable local, state, or federal laws. This policy applies to all aspects of employment, including, but not limited to, hiring, job assignment, compensation, promotion, benefits, training, discipline, and termination. F5 offers a variety of reasonable accommodations for candidates. Requesting an accommodation is completely voluntary. F5 will assess the need for accommodations in the application process separately from those that may be needed to perform the job. Request by contacting accommodations@f5.com.