System Security Engineer

Amentum is seeking a highly skilled System Security Engineer to support the design, implementation, and ongoing operations of enterprise security tools—including ACAS (Nessus/Tenable.sc), Trellix ePO (formerly McAfee ePolicy Orchestrator), and Microsoft Endpoint Configuration Manager (MECM/SCCM)—in a Department of Defense (DoD) environment. The successful candidate will play a critical role in enhancing cybersecurity posture, ensuring system compliance, and supporting vulnerability management and endpoint protection initiatives across a large-scale enterprise network as part of a team prototyping a next-generation collaboration capability for the Department of Defense

We value candidates who are detail-oriented while also being able to think and react quickly to emerging and unique problem sets.  You’ll be expected to work onsite, have a strong work ethic, and possess the ability to work as a critical member of our team. 

Responsibilities:

• Design and Architect Security Tool Deployments:
  
  • Develop and maintain secure, scalable architecture for ACAS, Trellix, and MECM solutions in classified and unclassified DoD environments.
  • Ensure tool integration with existing enterprise systems and SIEMs (e.g., Splunk, ArcSight).
• Implementation and Configuration:
  
  • Configure and deploy ACAS (Tenable.sc and Nessus) for automated vulnerability scans and compliance assessments.
  • Install, configure, and optimize Trellix ePO and associated modules (DLP, ENS, HIPS).
  • Set up and manage MECM infrastructure for patch management, endpoint deployment, and compliance monitoring.
• Operations and Monitoring:
  
  • Perform regular vulnerability scans, analyze findings, and generate risk-based remediation reports.
  • Monitor endpoint security posture, respond to alerts, and maintain up-to-date AV/AM/EDR policies.
  • Support patching cycles, software deployments, and inventory tracking via MECM.
• Security Compliance and Documentation:
  
  • Ensure systems are compliant with DoD STIGs, RMF/NIST 800-53 requirements, and DISA mandates.
  • Maintain documentation for configurations, processes, POA&Ms, and system security plans (SSPs).
  • Assist with audit preparation, system hardening, and control implementation.
• Cross-Team Collaboration:
  
  • Work closely with cybersecurity, systems, and network teams to identify threats and improve security posture.
• Use JIRA and Confluence tools to track assigned tasks and update progress and completion status
• Implement and maintain Government standards for system security
• Liaise with vendors and other IT personnel for problem resolution

Requirements:

• IAT Level II or higher certification (e.g., Security+ CE, CySA+, CASP+, CISSP, or equivalent)
• 7-10+ years of experience supporting security tools in DoD or Federal IT environments
• Proven hands-on experience with:
  
  • ACAS (Tenable.sc, Nessus)
  • Trellix ePO (formerly McAfee) and its endpoint protection modules
  • MECM/SCCM for patching, imaging, and software deployment
• Familiarity with DoD cybersecurity policies, STIGs, and RMF processes
• Experience with Microsoft Office applications such as Excel, Word, Outlook, and SharePoint
• Exceptional attention to detail; excellent verbal and written communication skills; strong organizational skills; critical thinking and problem-solving skills
• Ability to work both independently and as part of a team in a dynamic environment. 
• Ability to travel up to 25%

Clearance Required: 

• Active TS clearance with SCI eligibility 

Minimum E