Security System Administrator

Antenna Research Associates Inc•Nashua, NH

2d•$110,000 - $130,000•Onsite

About The Position

We are seeking an experienced Security System Administrator to support and maintain systems within the enterprise cybersecurity and compliance-driven environment. This role requires a technically proficient professional capable of operating within classified environments, ensuring system integrity, security, and compliance with federal DoD (DoW) standards.

Requirements

3+ years of experience as a System Administrator in a cybersecurity-focused or compliance-driven environment
Hands-on experience supporting classified systems (CUI, Secret, or higher)
Strong knowledge of: Windows Server and/or Linux administration
Strong knowledge of: Active Directory, DNS, DHCP, and Group Policy
Strong knowledge of: System hardening (STIGs), patch management, and vulnerability remediation
Experience with RMF, NIST 800-53 controls, and ATO processes
Ability to operate as a Subject Matter Expert (SME) across multiple technical domains
Proven ability to work both independently and within cross-functional teams
Strong troubleshooting, analytical, and problem-solving skills
Conduct site visits and attend meetings at various company locations.
Travel up to 10% of the time as required.
Experience with Special Access Programs (SAP) and SIPRNet

Nice To Haves

Relevant industry certifications such as: Security+ (DoD 8570/8140 compliant)
Relevant industry certifications such as: CompTIA CASP+, CompTIA A+, CompTIA Network+
Relevant industry certifications such as: Microsoft, Linux, or VMware certifications (e.g., MCSA/MCSE, RHCSA/RHCE, VCP)
advanced degree preferred

Responsibilities

Administer, maintain, and secure classified information systems in accordance with DoD and organizational policies
Perform routine system maintenance, including patching, updates, and vulnerability remediation (e.g., STIG compliance, SCAP scans)
Design, deploy, and manage Windows/Linux domains, including Active Directory configuration, Group Policy management, and system hardening
Support system accreditation efforts under RMF, including implementation of NIST 800-53 security controls
Monitor system performance, logs, and security events; respond to incidents as required
Implement and maintain secure configurations for servers, workstations, and network devices
Collaborate with ISSM/ISSO, network teams, and engineering staff to ensure continuous compliance and operational readiness
Maintain documentation including system configurations, SOPs, and change management records
Support audits, inspections, and security assessments (e.g., DCSA reviews)
Participate in system buildouts, upgrades, and infrastructure improvements
Assist with COMSEC as an ALT COMSEC Manager