Cyber Systems Security Engineering Specialist

MTSI Defense Services Division is seeking an experienced Cyber / Systems Security Engineering Specialist to support PMA-261 cyber engineering and platform/system security activities across 53 E/K program environments. The role blends hands-on technical administration/security operations with Systems Security Engineering (SSE) practices, supporting secure configurations, vulnerability management, compliance, and security documentation. Plus limited MBSE experience (ability to interpret interfaces and architecture intent from program models [SysML] and technical baselines).

Primary Responsibilities:

• Execute cybersecurity compliance and engineering activities across lab, integration, and operational support environments (RDT&E and/or program networks as assigned).
• Perform vulnerability management activities including ACAS scanning coordination, patching support, remediation tracking, and security posture reporting.
• Apply DISA STIGs/SRGs for Windows, Linux, hypervisors, and network devices; support scripted evaluation where applicable.
• Support secure network segmentation concepts (VLANs, trunking, routing boundaries), firewall policy implementation/validation, and VPN administration (as directed).
• Administer and maintain Linux-based systems and services (RHEL/CentOS/Ubuntu), including directory integration and authentication controls where required.
• Support virtualization platforms (VMware ESXi/vCenter) and backup/recovery practices; help ensure availability and configuration compliance.
• Contribute to SSE/RMF-relevant artifacts and periodic submissions (plans, evidence, control implementations, scan outputs, POA&M support).
• Read/interpret relevant architecture/interface products WBBB/RIBS-P to ensure security controls align with system boundaries and intended behavior.

Qualifications:

• 5+ years' experience in DoD/DoD-adjacent IT, system administration, and/or cybersecurity support
• Active Secret Clearance (TS preferred)
• Strong Linux administration background (RHEL preferred) and demonstrated STIG implementation experience
• Experience with ACAS vulnerability scanning and remediation workflows
• Working knowledge of enterprise networking fundamentals (routing/switching, VLANs, firewall policy concepts)
• Experience supporting virtualization (VMware ESXi/vSphere) and backup/recovery

Desired Skills:

• HBSS/ePO client product experience
• Familiarity with GitLab administration/secure CI/CD support in segmented environments
• Basic scripting/automation (Python, PowerShell, Ansible)
• Exposure to SSE/RMF processes and artifact preparation in program environments
• Experience supporting classified spaces and handling procedures

The pay range for this position in is $100,000/year to $170,000/year; however, base pay offered may vary depending on established government contract ranges, job-related knowledge, skills, and experience, and other factors. MTSI also offers a full range of medical, financial, and other benefits, dependent on the position offered. Base pay information is based on market location. Applications will be accepted on an ongoing basis. This posting will be renewed periodically until the position is filled.

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  Interesting Work:
  
  
  
  Our co-workers support some of the most important and critical programs to our national defense and security.
  
  
  
  
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  Values:
  
  
  
  Our first core value is that employees come first. We challenge our co-workers to provide the highest level of support and service, and reward them with some of the best benefits in the industry.
  
  
  
  
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  100% Employee Owned:
  
  
  
  We have a stake in each other's success, and the success of our customers. It's also nice to know what's going on across the company; we have company wide town-hall meetings three times a year.
  
  
  
  
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  Great Benefits - Most Full-Time Staff Are Eligible for:
  
  
  
  
  
• Starting PTO accrual of 20 days PTO/year + 10 holidays/year
  
  
• Flexible schedules
  
  
• 6% 401k match with immediate vesting up to $9k annually
  
  
• Semi-annual bonus eligibility (July and December)
  
  
• Company funded Employee Stock Ownership Plan (ESOP) - a separate qualified retirement account
  
  
• Up to $10,000 in annual educational reimbursement
  
  
• Other company funded benefits, like life and disability insurance
  
  
• Optional zero deductible Blue Cross/Blue Shield health insurance plan
  
  





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  Track Record of Success:
  
  
  
  We have grown every year since our founding in 1993.
  
  
  
  

Modern Technology Solutions, Inc. (MTSI) is a 100% employee-owned engineering services and solutions company that provides high-demand technical expertise in Digital Transformation, Modeling and Simulation, Rapid Capability Development, Test and Evaluation, Artificial Intelligence, Autonomy, Cybersecurity and Mission Assurance

MTSI delivers capabilities to solve problems of global importance. Founded in 1993, MTSI today has employees at over 20 offices and field sites worldwide.

For more information about MTSI, please visit

MTSI embraces nine core values including our first core value of Employees come first. Consistent with our Core Values, we are committed to Equal Opportunity, making decisions without regard to race, color, religion, sex, national origin, age, military/veteran status, disability, or any other characteristics protected by applicable law. MTSI is committed to Equal Employment Opportunity and providing reasonable accommodations to applicants and employees with physical and/or mental disabilities.