Senior Endpoint Security Systems Engineer

Job Description

Job Description

NOTE: Before applying to this role, you must currently have an Active Secret Clearance (TS/SCI), and your background should align with the job description; NO EXCEPTIONS!!!

Senior Endpoint Security Systems Engineer

Adelphi, MD (Hybrid – 3 days onsite) | Full-Time | Active TS/SCI Required

Our client is seeking a Senior Endpoint Security Systems Engineer to support the C5ISR Center Cyber Security Service Provider (CSSP) program. In this role, you'll lead the engineering, deployment, and sustainment of enterprise host-based defense capabilities across mission assets, with a primary focus on our Trellix environment (ePolicy Orchestrator and Endpoint Security suite) and a secondary focus on operationalizing Elastic Defend for Endpoint as part of a multi-tiered defense architecture. You'll work closely with mission system owners, infrastructure architects, and defensive cyber operations teams to protect Windows, Linux, and macOS platforms across on-premises environments and cloud IaaS.

What You'll Do :

• Console Administration — Maintain, upgrade, and harden central endpoint management consoles (primarily Trellix ePO) across multi-tier networks, isolated enclaves, and cloud-connected management VPCs.
• Multi-Tiered Endpoint Architecture — Engineer, deploy, and sustain the Trellix suite alongside Elastic Agent/Elastic Defend, establishing cohesive agent lifecycle management, mutual compatibility, and synchronized host-level protection.
• Endpoint Environment Integration — Direct the integration, configuration, and agent lifecycle management for endpoints and servers residing within on-premises environments and cloud IaaS instances, covering Windows, Linux, and macOS.
• Policy & Performance Tuning — Design, benchmark, and deploy scan exclusion policies, behavioral rules, DLP rules, and content updates to ensure host protection without degrading OS stability, server throughput, or cloud compute performance.
• Troubleshooting & Liaison — Resolve complex system-level issues, including:
• Diagnosing and remediating agent connectivity, registration, and communication failures across hybrid network boundaries
• Debugging product installation and deployment failures on mission hosts
• Partnering with mission owners to engineer precise performance exclusions and resolve mission-critical application blocks caused by security policies
• Investigating and rectifying ePO console misconfigurations, policy inheritance errors, or corrupt database events impacting the wider enterprise
• Compliance & Risk Alignment — Maintain compliance with DISA STIGs, OPORD, and endpoint security requirements across all supported host deployments (on-premises and IaaS), leveraging host reporting to support continuous monitoring frameworks.
• Threat Detection Support — Collaborate with CSSP threat detection and hunt teams to implement custom endpoint signatures, indicators of compromise (IOCs), and automated containment policies.

Required Qualifications:

• Active Top Secret/SCI clearance (U.S. citizenship required); Secret active to start acceptable
• Bachelor's degree in Cybersecurity, Computer Science, or a related STEM/IT field with 8+ years of relevant systems engineering/endpoint security experience, OR a Master's degree with 6+ years
• DoD 8140 compliance upon start: an active certification meeting CSSP-Infrastructure Support, CSSP-Analyst, or IAT Level II/III requirements (e.g., CEH, CySA+, GCIH, GCFA, GMON, CISSP, CASP+, or CISM)
• Hands-on experience administering and upgrading Trellix ePolicy Orchestrator (ePO), Trellix Agent, and core modules including Endpoint Security (Threat Prevention and Firewall), Data Loss Prevention (DLP), and Policy Auditor
• Proven experience deploying and maintaining endpoint security agents across enterprise Linux (RHEL/CentOS/Rocky), Windows (Server and Desktop), and macOS environments
• Practical experience managing and troubleshooting host-based security across on-premises and cloud IaaS (VM) instances
• Strong troubleshooting skills for OS performance impacts, resource contention, and agent-server communication across complex network topologies

Preferred Qualifications:

• Experience with Trellix Solidcore (Application Control) for application whitelisting and file integrity monitoring (FIM)
• Hands-on experience deploying, configuring, and tuning Elastic Agent and Elastic Defend for Endpoint
• Familiarity with macOS enterprise security configurations and deployment tools (Apple MDM, JAMF Pro)
• Experience integrating or reporting endpoint security posture into DISA COAMS and CMRS
• Familiarity with cloud networking, auto-scaling, and security groups in AWS, Azure, or GCP
• Scripting ability in PowerShell, Bash, or Python for automating agent installation, verification, and health monitoring
• Working knowledge of the MITRE ATT&CK framework and its application to host-based detections

\nCompany Description

Our clients story and is a veteran-owned business.

1. Established on July 21, 1989, is certified Service-Disabled Veteran-Owned Small Business (SDVOSB) and a HUBZone-Certified Small Business Concern. Upholding these small business certifications, Premier offers customers flexibility when choosing a solutions provider. With Secret and Top-Secret Facility Clearances obtained in 2002 and 2005, respectively, we are equipped to support a diverse range of task orders.

2. Compliance with the Defense Contract Audit Agency (DCAA) further underscores our commitment to quality service delivery.

3.Embracing a philosophy of customer partnership, Premier has carved out a niche for itself by consistently delivering exceptional quality solutions. Our dedication to maintaining high standards is reflected in the numerous awards and accolades received over the past two decades.

Company Description

Our clients story and is a veteran-owned business.\n\n1. Established on July 21, 1989, is certified Service-Disabled Veteran-Owned Small Business (SDVOSB) and a HUBZone-Certified Small Business Concern. Upholding these small business certifications, Premier offers customers flexibility when choosing a solutions provider. With Secret and Top-Secret Facility Clearances obtained in 2002 and 2005, respectively, we are equipped to support a diverse range of task orders.\n\n2. Compliance with the Defense Contract Audit Agency (DCAA) further underscores our commitment to quality service delivery.\n\n3.Embracing a philosophy of customer partnership, Premier has carved out a niche for itself by consistently delivering exceptional quality solutions. Our dedication to maintaining high standards is reflected in the numerous awards and accolades received over the past two decades.