Cybersecurity Systems Engineer (NH3)

Security Clearance Required: TS/SCI w/ Polygraph

About the role

The Cybersecurity Systems Engineer will serve as a technical leader and subject matter expert within the Endpoint Detection and Response (EDR) Program. Operating in a multi-domain infrastructure, the successful candidate will drive the strategic architectural design, end-to-end integration, deployment, and optimization of premier endpoint security platforms, specifically Microsoft Defender for Endpoint (MDE) and Trellix HX. This critical role bridges high-level systems architecture with operational capabilities, ensuring total endpoint visibility, robust threat containment, and resilient configuration management across all enterprise and critical assets to defend the security infrastructure against sophisticated cyber threats.

The Engineer is responsible for leading the lifecycle engineering and scale-out architecture of MDE and Trellix HX across hybrid environments, including on-premises, cloud, and virtual desktop infrastructures (VDI). This includes authoring complex system engineering and implementation plans, tuning agent configurations and exclusion policies to eliminate mission friction, and monitoring overall endpoint health at scale. Additionally, the individual will act as a primary technical advisor to stakeholders on system risks and engineering considerations, provide advanced forensic support to the SOC during critical high-priority incidents, and actively mentor junior and mid-level engineering personnel within the program.

Responsibilities

• Lead the lifecycle engineering and scale-out architecture of Microsoft Defender for Endpoint (MDE) and Trellix HX across hybrid environments (on-premises, cloud, VDI).
• Author complex system engineering and implementation plans.
• Tune agent configurations and exclusion policies to eliminate mission friction.
• Monitor overall endpoint health at scale.
• Act as a primary technical advisor to stakeholders on system risks and engineering considerations.
• Provide advanced forensic support to the SOC during critical high-priority incidents.
• Mentor junior and mid-level engineering personnel within the program.

Requirements

• Proven engineering experience with Microsoft Defender for Endpoint (MDE) architecture, deployment strategies via MECM/SCCM or Intune, policy ring management, and advanced hunting using Kusto Query Language (KQL).
• Demonstrated experience engineering, deploying, and managing Trellix HX (formerly FireEye) controllers and agents within air-gapped or highly restricted networks, including the creation of OpenIOC and YARA rules.
• In-depth technical understanding of Windows, Linux, and macOS internals, including file systems, registry structures, and process execution mechanics.
• IAM Level II or III baseline certifications.
• Twenty (20) years of experience as a systems engineer or cybersecurity engineer.
• Bachelor's degree in a related technical discipline from an accredited college or university (five additional years of System Engineering experience may be substituted).

About the company

Legato, LLC is a dynamic small business headquartered in Columbia, near Ft. Meade, MD. Our positions include Cyber, Software, Systems, Networking, Data Science, and other complex engineering capabilities. We set ourselves apart by having employees in the top of their field who enjoy working at Legato for its attention to its employees, aggressive compensation, and upward mobility possibilities.

Benefits

• Individual and family health, vision, and dental benefits.
• A minimum of four (4) weeks of paid time off, including a week of sick leave.
• 11 federal holidays off.
• 401(k) employer match with no vesting schedule.
• Opportunity to earn referral benefits or bank hours if the contract allows.

Pay

Salary Range: $220,000–$240,000, depending on experience.