Senior System Administrator

SITEC is seeking a Senior Systems Administrator to support lifecycle sustainment activities for commercial and custom-developed education, learning, and training applications. This role will join an existing technical team responsible for maintaining secure, reliable, and high-performing IT systems across hybrid on-premises and cloud-based environments.

The ideal candidate is a self-motivated Systems Administrator with strong Windows and Linux experience, hands-on patching and vulnerability remediation knowledge, and the ability to support mission-critical systems in a fast-paced DoD environment.
Responsibilities

The Senior Systems Administrator will provide operational support, maintenance, troubleshooting, patching, automation, and system administration across enterprise Windows, Linux, and cloud-hosted environments. This position will support system reliability, security compliance, infrastructure modernization, and lifecycle sustainment activities.
Key Duties

• Administer and maintain Windows Server and Linux server environments.
• Perform IAVA patching, vulnerability remediation, and compliance reporting across enterprise systems.
• Provide troubleshooting, maintenance, and operational support for on-premises and cloud-hosted IT environments.
• Execute system patching, software maintenance, upgrades, hardening, and disk management.
• Implement and manage Windows Group Policy Objects and Active Directory-related administration.
• Develop automation scripts using PowerShell, Bash, Python, or related scripting languages.
• Support AWS cloud infrastructure using services such as EC2, Lambda, CloudFormation, and IAM.
• Assist with infrastructure as code initiatives using Ansible and Terraform.
• Develop and maintain system automation tools to improve reliability, efficiency, and uptime.
• Work collaboratively with technical teams in a fast-paced, mission-focused environment.

Required Qualifications

• Active TS/SCI with Polygraph.
• 15 years of Systems Administration experience supporting programs of similar scope, type, and complexity.
• Bachelor's degree in a technical discipline; 5 additional years of SA experience may be substituted in lieu of a degree.
• DoD 8570 compliance with IAT Level I.
• Experience maintaining Windows Server environments, including hardening, patching, upgrades, and disk management.
• Experience administering Linux servers, including patching and software maintenance.
• Experience with IAVA patching and reporting.
• Experience maintaining and upgrading installed software across enterprise systems.
• Strong troubleshooting and problem-solving skills across computer systems and software.

Desired Skills

• Strong hybrid Linux/Windows Systems Administration background.
• Hands-on experience with AWS services such as EC2, Lambda, CloudFormation, and IAM.
• Experience with automation and scripting tools including Ansible, Terraform, PowerShell, Bash, and Python.
• Experience with Active Directory and Group Policy Management.
• Understanding of cloud security practices, patch management, and compliance reporting.
• Ability to work independently and collaboratively in a fast-paced technical environment.

About SITEC

SITEC is an employee- and customer-focused Information Technology and Professional Services firm specializing in cybersecurity, software and systems engineering, systems administration, and lifecycle support services. We design, develop, and deliver mission-focused technology solutions that support the continuous operation and modernization of critical customer platforms.