Secure Systems Administrator - Windows & Linux, TS/SCI

Sigma Defense Systems; March Air Reserve Base (CA); On-site; USD 115,000 - 135,000; Full time

Benefits offered by this job

Dental & Vision Insurance

Medical with HSA/FSA/DFSA

Life & AD&D

EAP

401(k) matching

PTO 160 hours

Holidays 12

Educational assistance

Competitive salary

Job summary

Sigma Defense Systems seeks a System Administrator to join our team at March Air Reserve Base. You will administer Windows and RHEL, perform routine patching, and maintain a secure, mission‑ready infrastructure supporting Department of War operations.

You will work with engineering and cybersecurity teams to uphold DISA STIGs and CDS operations, ensure system availability, and support backups and DR activities. Requires US citizenship and Security+; TS/SCI preferred.

Qualifications

• 3-7 years of relevant experience.
• Experience administering Windows Server and/or RHEL systems.
• Experience installing, configuring, maintaining, and troubleshooting server operating systems.
• Experience with virtualization technologies such as VMware ESXi.
• Experience performing operating system patching, maintenance, and lifecycle support.
• Basic understanding of networking concepts and enterprise infrastructure.
• Experience supporting secure or air-gapped Department of War environments.
• Experience with Cross Domain Solution (CDS) technologies.
• Experience with Full Motion Video (FMV) systems, platforms, or supporting infrastructure.
• Experience implementing or maintaining DISA Security Technical Implementation Guides (STIGs).
• Experience maintaining secure Windows and/or RHEL system baselines.
• Experience administering RHEL in physical or virtualized environments.
• Experience with storage, backup, and disaster recovery solutions.
• Must be a U.S. citizen.

Responsibilities

• Install, configure, maintain, and troubleshoot Windows and RHEL systems.
• Perform routine operating system patching, software updates, and system maintenance.
• Maintain physical and virtual server infrastructure.
• Configure and maintain user accounts, storage, system services, and server resources.
• Troubleshoot hardware, operating system, and application issues.
• Support implementation of DISA STIGs and approved system configuration changes.
• Maintain system documentation, configuration baselines, and standard operating procedures.
• Support system backups, recovery operations, and disaster recovery activities.
• Support secure Cross Domain Solution (CDS) operations and associated system administration activities.
• Coordinate with cybersecurity and network engineering personnel to implement approved system changes and maintain secure, reliable system operations.
• Support testing, integration, and implementation of approved hardware and software changes.
• Monitor system health, investigate operational issues, and resolve problems to maintain system availability and performance.

Skills

Windows Server administration

RHEL administration

VMware ESXi

Patching & lifecycle management

Networking fundamentals

Scripting (Bash, PowerShell, Ansible)

Security controls (STIGs)

Cross Domain Solution (CDS) support

Education

Bachelor's degree in Information Technology or related field

Tools

Ansible

Job description

Sigma Defense Systems seeks a System Administrator to join our team at March Air Reserve Base. You will administer Windows and RHEL, perform routine patching, and maintain a secure, mission‑ready infrastructure supporting Department of War operations.

You will work with engineering and cybersecurity teams to uphold DISA STIGs and CDS operations, ensure system availability, and support backups and DR activities. Requires US citizenship and Security+; TS/SCI preferred.