Endpoint Security Engineer

Career Opportunities with Castalia Systems

A great place to work.

Current job opportunities are posted here as they become available.

Remote in the areas of Morrisville, NC or Falls Church, VA

TS/SCI

Medical, dental, and vision coverage, 401k matching, generous PTO, paid holidays, professional training opportunities, and even pet insurance to ensure your furry friends are cared for too.

Castalia Systems is seeking an Endpoint Security Engineer to support our Intelligence Client’s mission sets. As an Endpoint Security Engineer you will design, deploy, and operationalize active, behavior-based endpoint detection and response (EDR/XDR) capabilities across one of the largest private operational fleets in North America. Protecting an enterprise comprising 600,000+ employees and 30,000+ physical sites, you will maintain rigorous security posture across traditional end-user computing (EUC) devices (laptop, desktop, mobile devices & retail terminals), on-premise physical & virtual servers & containerized workloads, and dynamic multi-cloud workloads (AWS, Azure, GCP).

In this role, you will balance proactive protection with business continuity—partnering directly with end-users and application owners to tune policies and eliminate operational friction, while providing tier-3/tier-4 technical escalations to Security Operations Center (SOC) analysts and IT Operations staff during active investigations.

A qualified candidate will perform the following duties and responsibilities, but are not limited to:

• Engineer, deploy, and maintain Next-Gen Antivirus (NGAV) and Endpoint Detection & Response (EDR/XDR) agents (e.g., Crowd Strike Falcon, Microsoft Defender for Endpoint, Sentinel One) across hundreds of thousands of heterogeneous endpoints.
• Implement active behavioral protections against zero-day malware, living-off-the-land binaries (LotLBs), fileless execution, and credential dumping.

• Serve as the primary technical partner to application owners and business units, establishing baseline behavior profiles to minimize false positives, performance degradation, or operational downtime across critical retail, logistics, and supply chain applications.
• Manage allow listing, exception workflows, and phased ring deployments (canary/pilot/production) to ensure silent, high-efficacy protection without disrupting day-to-day warehouse or logistics operations.

• Act as endpoint security escalation lead for SOC analysts during high-severity threat detection and response events.
• Act as endpoint operations escalation lead for IT administrators during high-impact event investigation and remediation efforts.
• Perform advanced host forensics, process-tree reconstruction, memory analysis, and script-based live remediation (e.g., host isolation, automated artifact collection, registry rollbacks).
• Extend endpoint security standards across private data center virtualization layers (VMware/Nutanix) and ephremal multi-cloud infrastructure (EC2, Azure VMs, Compute Engine, containerized hosts).
• Continuously measure and test security control efficacy using automated attack simulation (BAS) tools and Purple Team exercises.
• Track and report on agent health, tamper-resistance, telemetry pipeline integrity, and coverage metrics aligned with enterprise asset management systems.

• A minimum of 7+ years of progressive experience in technical cybersecurity engineering or infrastructure security roles.
• At least 3–5 years directly engineering and administering enterprise-grade EDR/XDR platforms across 50,000+ endpoints in a distributed hybrid environment.
• Demonstrated track record supporting active SOC investigations and collaborating cross-functionally with system owners in large-scale enterprise environments.
• Bachelor’s degree in Computer Science, Cybersecurity, Information Systems, or equivalent practical enterprise experience.
• EDR/XDR Engineering: Expert-level proficiency administering enterprise-scale endpoint platforms across…