Overview Senior Windows Systems Administrator

LOCATION: Columbia, MD (Onsite)

JOB STATUS: Full-time

CLEARANCE: Active Top Secret / TS/SCI (Required)

TRAVEL: Less than 10%

SALARY RANGE: $145k - $165k

Astrion has an exciting opportunity for a highly experienced Senior Windows Administrator to build, secure, and sustain the Windows Server estate, the Windows 11 workstation fleet, and the Active Directory and Windows network services that run across three or more isolated classified networks supporting Department of Defense/Department of War (DoD/DoW) environments in Columbia, MD. The adecuado candidate brings deep Windows Server and Active Directory expertise, extensive experience operating inside closed and air-gapped classified enclaves, and a proven record of building and maintaining systems in compliance with Risk Management Framework (RMF), DoD STIG, and Comply-to-Connect (C2C) requirements. This position requires Monday through Friday on-site work at our facility in Columbia, MD.

REQUIRED QUALIFICATIONS / SKILLS

Active TS/SCI security clearance (required)

Bachelor's degree in Computer Science, Information Technology, or related field (or equivalent experience)

8+ years of Windows systems and network administration experience within DoD/DoW or classified environments

Deep expertise in

Windows Server administration (2016 through 2022): installation, patching, performance tuning, roles and features, storage, and networking

Active Directory Domain Services: Group Policy, DNS, DHCP, DFS, ADCS, sites and replication, and trusts

Scripting and automation (PowerShell and desired-state configuration)

Windows endpoint management (Microsoft Endpoint Configuration Manager, imaging, Group Policy)

End-user support on Classified Windows 11 and Windows Server supporting Operating System, supported applications, and hardware issues

Demonstrated experience implementing and maintaining DoD STIG compliance on Windows Server and workstations

Experience with offline and air-gapped patching (WSUS or MECM in an isolated enclave)

Strong understanding of

RMF (Risk Management Framework)

DISA security requirements and accreditation processes

DCSA accreditation standards

Active DoD 8140 (formerly DoD 8570) compliant baseline certification (e.g., Security+ CE, CISSP)





Active DoD 8140 compliant computing environment certification (e.g., minimum Microsoft certification such as Windows Server Hybrid Administrator Associate or MCSA/MCSE equivalent)

Experience with

ACAS or Nessus and SCAP scanning

SIEM integration and Windows event and log analysis

Continuous monitoring under RMF

KEY COMPETENCIES

Advanced Windows Server and Active Directory administration and troubleshooting

Security hardening and compliance enforcement

Automation and scripting (PowerShell) Strong troubleshooting skills used in end-user support Strong analytical and problem-solving abilities

Excellent communication and documentation skills

Ability to operate in high-security, mission-critical environments

PREFERRED QUALIFICATIONS / SKILLS

On-Premise deployment and administration of Microsoft SharePoint environments

Microsoft certifications such as Windows Server Hybrid Administrator Associate, Azure Administrator (AZ-104), or Identity and Access Administrator

Hyper-V and Windows Failover Clustering, and storage experience (NetApp or SAN)

PKI and Active Directory Certificate Services design and administration

PowerShell automation at scale (desired-state configuration, Git-based configuration management)

Zero Trust architectures and application allowlisting (AppLocker or WDAC) in classified environments

Prior experience supporting Cross Domain Solutions (CDS) programs

Experience with cloud-based DoD environments (e.g., Azure Government, Azure Secret)

Project management experience and experience briefing executive leadership

RESPONSIBILITIES

Administer, patch, and sustain Windows Server (2016 through 2022) and Windows 11 workstations across three or more isolated classified networks, each operated as its own authorization boundary

Provide end-user support for classified Windows Server and Windows 11 workstations to include troubleshooting supported applications,



hardware, and operating system issues.

Administer Active Directory Domain Services across a separate forest per enclave: Group Policy, DNS, DHCP, DFS, Active Directory Certificate Services, sites and replication, and trust health

Build, harden, and baseline Windows systems to DoD Security Technical Implementation Guides (STIGs); remediate findings and control configuration drift

Manage the Windows workstation fleet with Microsoft Endpoint Configuration Manager (MECM), image build and deployment (MDT/WDS), application packaging, and Group Policy on closed networks

Perform patching and updates on air-gapped networks through approved offline processes (WSUS in an isolated enclave, MECM, or trusted media transfer), with a defined cadence and an emergency-patch path

Administer Windows network services: DNS, DHCP, name resolution, time synchronization, PKI and certificate services, and Windows Firewall with IPsec policy

Administer virtualization and clustering where present (Hyper-V, Windows Failover Clustering), including capacity planning and recovery testing

Automate provisioning, configuration, and remediation with PowerShell and desired-state configuration, including on disconnected systems

Administer host-based endpoint protection (Microsoft Defender for Endpoint or approved ESS) and integrate with the security tool stack

Implement and maintain C2C and 802.1x posture for Windows endpoints

Perform vulnerability remediation and continuous monitoring in accordance with RMF controls; run and interpret ACAS and SCAP scans and review Windows event and audit logs

Support the Authority to Operate (ATO) process, including STIG checklists, POA&Ms;, and risk assessments

Maintain backup and recovery for Windows systems and Active Directory, including system state and authoritative and non-authoritative restore

Develop and maintain system documentation, diagrams, SOPs, and security artifacts

Troubleshoot complex issues across multi-network, multi-vendor environments

Collaborate with cybersecurity, network engineering, systems engineering, and mission stakeholders to ensure secure, reliable operations

Support audits, inspections, and compliance validation activities

📌 Sr. Windows Systems Administrator (Colombia)
🏢 Astrion
📍 Colombia