IT Offensive Security Engineer III (Must Reside in Texas)

Randolph Brooks Federal Credit Union•San Antonio, TX

2d•Hybrid

About The Position

Randolph-Brooks Federal Credit Union is seeking an experienced Offensive Security Engineer III to join its IT Security team. The role leads complex, intelligence-informed adversary emulations to assess how the organization’s people, processes, architecture, and technology withstand realistic, multi-stage attacks. Campaigns may cover identity, endpoints, networks, applications, APIs, cloud platforms, data environments, software delivery systems, and other authorized surfaces. Controlled human-factor and physical scenarios may be included when explicitly approved. The engineer evaluates attack paths and the effectiveness of preventive, detective, responsive, and recovery controls, then turns demonstrated compromise paths into systemic improvements across security and engineering. The position provides technical and engagement leadership, develops custom offensive tooling and infrastructure, manages operational risk, and coordinates with threat intelligence, SOC, incident response, security engineering, legal, privacy, physical security, and business stakeholders. It also advances offensive and defensive maturity through purple-team collaboration, detection validation, reporting, mentorship, and repeatable assessment methods. The position may work a hybrid schedule (remote/onsite) after a training period, whose duration may vary. Training takes place at the RBFCU Administrative Service Center in Live Oak, Texas. Applicants must reside in Texas and be able to perform all work from their Texas home. Employees working from home must have a reliable internet provider, the required minimum internet connection, the ability to connect directly to the modem by Ethernet, and a safe, suitable, distraction-free workspace.

Requirements

Bachelor's degree in Computer Science, Management Information Systems, Cybersecurity, Information Technology, or a related field, or an equivalent combination of education and experience.
Minimum 3–5 years conducting adversary emulation, penetration testing, red team operations, or advanced security assessments.
Deep hands-on experience leading multi-stage adversary emulations and complex assessments across several enterprise technology domains.
Advanced knowledge of identity attacks, endpoint tradecraft, network protocols, application and API exploitation, cloud attack paths, persistence, command and control, evasion, and data access techniques.
Experience designing rules of engagement, managing testing risk, coordinating deconfliction, protecting sensitive data, and making stop-work decisions during live exercises.
Production-quality engineering experience using Python, Go, C#, C/C++, Rust, PowerShell, JavaScript, APIs, infrastructure automation, or comparable technologies.
Experience developing or modifying offensive tools, payloads, infrastructure, attack automation, and validation methods while maintaining operational security.
Advanced technical judgment to balance realism, stealth, evidence, business impact, legal and ethical boundaries, safety, and operational continuity.
Strong communication, facilitation, and stakeholder engagement skills, including constructive debriefs and concise communication to senior leadership.
Must reside in Texas and be able to perform all work from a home in Texas.
For home work, must have a reliable internet provider, the minimum internet connection required by RBFCU, the ability to hard-wire directly to the modem, and a safe, suitable, distraction-free workspace.

Nice To Haves

Experience emulating advanced threat actors in hybrid and multi-cloud environments, identity systems, software supply chains, data platforms, AI systems, or critical infrastructure.
Experience with advanced application exploitation, exploit development, malware research, reverse engineering, cloud red teaming, wireless testing, or hardware security.

Responsibilities

Lead complex, multi-domain adversary-emulation campaigns targeting critical services, high-value assets, privileged identities, cloud control planes, applications, data, and software delivery systems.
Translate threat intelligence and business context into campaign objectives, adversary profiles, attack hypotheses, target selections, techniques, success criteria, and measurable defensive outcomes.
Design engagement plans, rules of engagement, safety controls, communications, deconfliction, escalation paths, data-handling requirements, and technical workstreams.
Execute and supervise advanced attack activity involving stealth, persistence, identity compromise, lateral movement, cloud privilege escalation, application exploitation, data access, and objective demonstration.
Lead controlled social-engineering, physical, wireless, third-party, or assumed-breach scenarios when explicitly approved by the required authorities.
Develop custom tooling, implants, payloads, test harnesses, automation, redirectors, infrastructure, and operational-security practices for authorized objectives.
Evaluate defense-in-depth performance across prevention, identity, segmentation, telemetry, detection, investigation, containment, eradication, recovery, and resilience.
Lead purple-team exercises and turn observations into detections, hunts, playbooks, architecture improvements, control validation, and remediation priorities.
Produce executive and technical narratives connecting attack paths and defensive gaps to business risk, systemic causes, and prioritized corrective actions.
Mentor offensive and defensive engineers, conduct technical reviews, and lead lessons-learned activities to improve engagement safety, realism, repeatability, and impact.