Information Systems Administrator

Aptima Inc.; Dayton (OH); On-site; USD 90,000 - 120,000; Full time

Job summary

Aptima Inc. is seeking a Systems Administrator to support maintenance and sustainment of classified and internal server environments in a security-conscious setting.

The role emphasizes system administration, cybersecurity hardening, and compliance activities to ensure operations meet DoD and NIST requirements. The candidate will collaborate with the ISSM and Aptima Cybersecurity and Compliance Team Lead to implement secure configurations, manage access controls, and document system processes.

Qualifications

• Experience administering Windows and/or Linux server environments in professional, academic, internship, or lab settings.
• Security certification meeting DoD 8570 IAT Level II requirements (minimum CompTIA Security+).
• Experience supporting IT/IS security compliance in secure or regulated environments.
• Familiarity with vulnerability scanning tools such as Tenable or Nessus.
• Understanding of IT/IS governance, risk management, and compliance frameworks including NIST 800-53/800-171.
• Strong organizational, communication, and interpersonal skills.
• Willingness to travel as needed.
• Active SECRET clearance; TS/SCI preferred.

Responsibilities

• Administer and manage Windows and Linux server environments across platforms.
• Maintain security baselines, configurations, and hardening standards.
• Apply DISA STIGs and CIS Benchmarks to systems.
• Perform vulnerability scanning and remediation using tools like Tenable/Nessus.
• Conduct regular audits to ensure IT/IS security compliance.
• Collaborate with IT/IS and cybersecurity teams on secure configurations.
• Manage user access control, identity management, and security protocols.
• Prepare documentation on system configuration, mapping, and processes.
• Assist with accreditation supporting RMF, NIST 800-53, and 800-171.
• Coordinate with auditors during reviews; stay current with standards.

Skills

Windows Admin

Linux Admin

System Hardening

Vulnerability Management

Documentation

Communication

Attention to Detail

Travel Willingness

Team Collaboration

Education

DoD 8570 IAT Level II

CompTIA Security+

Tools

Tenable

Nessus

Job description

Aptima is a technological leader in the national security industry. Our mission is to drive the future of national security by engineering scalable solutions that fuse technological innovation with human potential to transform how individuals and teams train, develop, and perform in mission-critical environments.

Our culture is rooted in our core values, which have evolved over time and our employees have embraced: Integrity, Ingenuity, Excellence, Respect, Engagement, Teamwork. At our core, Aptima researches, develops, and innovates within an area that engineering firms largely ignore, the human component. To impact the world in meaningful ways, you must bring those innovations to light, and that is precisely what we do.

How You'll Make an Impact

The primary responsibility of this role will be to support the maintenance and sustainment of classified and internal server environments, encompassing system administration, cybersecurity hardening, and compliance activities.

This position will assist in managing Windows and Linux systems supporting secure research and development environments. Responsibilities include maintaining system security baselines, supporting vulnerability management activities, assisting with accreditation documentation, and ensuring systems operate in compliance with applicable cybersecurity standards.

The selected candidate will collaborate closely with the Information Systems Security Manager (ISSM), the Aptima Cybersecurity and Compliance Team Lead, and internal program teams to ensure systems remain secure, compliant, and operational.

The role requires strong technical problem-solving skills, attention to detail, and the ability to work both independently and collaboratively within a team supporting classified and mission-critical systems.

Key Responsibilities

• Administer and manage server environments across Windows and Linux platforms
• Support the maintenance, sustainment, and security configuration of classified and internal server environments
• Apply and maintain system hardening standards such as DISA STIGs and CIS Benchmarks
• Perform vulnerability scanning and remediation using tools such as Tenable, Nessus, or similar platforms
• Conduct regular system audits to ensure compliance with IT/IS security frameworks and governance requirements
• Collaborate with IT/IS and cybersecurity teams to plan and implement secure system configurations
• Manage user access control, identity management, and security protocols
• Prepare and maintain documentation related to system configuration, mapping, processes, and service records
• Assist with accreditation and compliance documentation supporting RMF, NIST 800-53, and NIST 800-171 requirements
• Coordinate with internal and external auditors to support compliance reviews and assessments
• Stay current with evolving cybersecurity standards, tools, and regulatory requirements

Requirements

• Demonstrated experience administering and securing Windows and/or Linux server environments in professional, academic, internship, or laboratory environments
• Security certification meeting DoD 8570 IAT Level II requirements (minimum CompTIA Security+)
• Experience supporting IT/IS security compliance within secure or regulated environments
• Familiarity with vulnerability scanning tools such as Tenable, Nessus, or similar platforms
• Understanding of IT/IS governance, risk management, and compliance frameworks including NIST 800-53 or NIST 800-171
• Strong organizational skills and attention to details
• Strong communication and interpersonal skills
• Willingness to travel as needed
• Active SECRET clearance required; TS/SCI clearance preferred

All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, age, national origin, disability, protected veteran status or any other status protected by applicable national, federal, state or local law.