System Administrator - Secure Windows & Linux | TS/SCI

Sigma Defense; Moreno Valley (CA); On-site; USD 115,000 - 135,000; Full time

Benefits offered by this job

Dental and Vision Insurance

Medical Insurance (HSA/FSA/DFSA)

Life and AD&D

EAP

401(k) Matching

PTO (160 hours)

Holidays (12)

Educational Assistance

Competitive Salary

Job summary

Sigma Defense is seeking a System Administrator to join our team at March Air Reserve Base. The role focuses on maintaining secure Windows and RHEL environments, applying patches, and ensuring mission-ready systems in collaboration with cybersecurity and engineering teams.

Qualified candidates will have 3–7 years of relevant experience, a bachelor’s degree in IT, and a TS/SCI clearance or the ability to obtain one. Citizenship is required; security clearance sponsorship may be available.

Qualifications

• Bachelor’s degree in Information Technology or related field.
• 3–7 years of relevant experience.
• Active TS/SCI clearance or ability to obtain one.

Responsibilities

• Install, configure, maintain, and troubleshoot Windows and RHEL systems.
• Perform routine OS 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, OS, and application issues.
• Support implementation of DISA STIGs and approved system changes.
• Maintain system documentation, baselines, and SOPs.
• Support backups, recovery operations, and disaster recovery activities.
• Support CDS operations and related admin activities.
• Coordinate with cybersecurity and network teams to implement changes.

Skills

Windows Server

RHEL

VMware ESXi

Patch management

Networking concepts

Cross Domain Solution (CDS)

FMV systems

STIGs

Baselines

Bash

PowerShell

Ansible

TS/SCI clearance

U.S. citizen

Education

Bachelor’s degree in Information Technology

Tools

VMware ESXi

Bash

PowerShell

Ansible

Job description

Sigma Defense is seeking a System Administrator to join our team at March Air Reserve Base. The role focuses on maintaining secure Windows and RHEL environments, applying patches, and ensuring mission-ready systems in collaboration with cybersecurity and engineering teams.

Qualified candidates will have 3–7 years of relevant experience, a bachelor’s degree in IT, and a TS/SCI clearance or the ability to obtain one. Citizenship is required; security clearance sponsorship may be available.