Senior Cybersecurity Engineer (ACAS/Trellix SME)

ZTI Solutions•Fort Meade, MD

19h•Onsite

About The Position

ZTI Solutions is seeking a Senior Cybersecurity Engineer to serve as the primary ACAS (Tenable.sc/Nessus) and Trellix engineer supporting a multinational IL5/IL6 collaboration effort in an operational Department of War (DoW) environment hosting multiple Coalition Mission Partner Environments (MPE). This is a demanding, high-energy, hands-on role focused on enterprise vulnerability management, endpoint security operations, and overall cyber posture across multiple enclaves. The Senior Cybersecurity Engineer serves as the primary ACAS (Tenable.sc/Nessus) and Trellix operations point of contact and subject matter expert for enterprise vulnerability management and endpoint security across classified, multinational, and mission-critical enclaves. Beyond ACAS and Trellix administration, the role supports security monitoring, incident response, vulnerability assessments, endpoint protection, and RMF/STIG compliance activities across cloud, hybrid, and on-premise environments. The ideal candidate brings advanced technical acumen, strong analytical and problem-solving skills, and the ability to independently manage and optimize enterprise ACAS and Trellix security operations, working closely with infrastructure, operations, and mission partner teams to identify risks, investigate threats, and keep enterprise systems compliant and operationally secure.

Requirements

U.S. Citizen.
Active Secret security clearance with the ability to obtain TS/SCI (TS/SCI preferred).
Active DoD 8140 IAT Level II or higher certification (e.g., Security+ CE, CCNA Security, CySA+, CISSP).
5+ years of overall IT experience (systems administration, engineering, networking, or technical support), including at least 4 years of progressive hands-on experience in cybersecurity operations, ACAS vulnerability management, Trellix endpoint security administration, and cybersecurity engineering.
Ability to work full-time, onsite in Ft. Meade, MD, 5 business days per week.
Hands-on experience administering the Trellix ESS platform — policy management, agent deployment, and administration through ePolicy Orchestrator (ePO).
Experience managing and troubleshooting Trellix endpoint protection technologies, including ENS, DLP, and Host IPS.
Experience operating and maintaining ACAS / Tenable scanning infrastructure — Tenable.sc/Nessus scanners, plugin management, credentialed scans, and scan scheduling.
Experience analyzing ACAS scan results, validating findings, and supporting remediation and POA&M tracking.
Familiarity with SIEM platforms such as Microsoft Sentinel.
Familiarity with DoD cybersecurity frameworks and RMF processes; able to take full ownership of tasks and deadlines and deliver high-quality results with limited supervision.
Understanding of vulnerability remediation workflows and endpoint security operations.
Strong decision-making, problem-solving, and stakeholder communication skills, including the ability to brief senior-level executives and customers.

Nice To Haves

Bachelor's degree in Computer Science, Information Security, or another STEM discipline.
Active Top Secret clearance with the ability to obtain SCI.
Experience supporting systems in a DISA-administered DoW environment.
Experience with Azure environments.
Experience with STIG compliance and system hardening.
Prior experience supporting ATO packages and control implementation statements.

Responsibilities

Act as the primary cyber operations POC for ACAS and Trellix operations within a secure, multinational DoW environment.
Serve as the primary SME for enterprise vulnerability management and Trellix endpoint security operations.
Administer and maintain ACAS infrastructure (Tenable.sc/Nessus), including scanners, plugin updates, credentialed scans, and scan scheduling.
Produce ACAS vulnerability reports, metrics, and POA&M tracking artifacts supporting RMF compliance.
Administer and maintain the ESS platform, including ePO policy management, endpoint protection, and agent health.
Monitor and investigate Trellix endpoint alerts, suspicious activity, and security events.
Tune Trellix detections, exclusions, and alerting logic to reduce false positives.
Support vulnerability remediation efforts with infrastructure and MPE teams.
Monitor and configure alerts and security events within Microsoft Sentinel.
Maintain endpoint security configurations, updates, and compliance across enterprise systems.
Support RMF documentation, security assessments, and compliance activities.
Monitor overall system security posture and identify emerging risks.
Other duties, as assigned.