Senior Systems Administrator

Position Overview

We are seeking a Senior Systems Administrator (SELinux / MLS SME) to support a mission‑critical enterprise Multi‑Level Security (MLS) configuration team. This role supports highly secure computing environments, including the Centralized Super Computing Facility (CSCF) and other classified programs.

In this position, you will serve as a Linux security expert, specializing in SELinux and MLS configurations within large‑scale enterprise and high‑performance computing environments. You will help design, implement, and troubleshoot secure Linux systems while supporting advanced computing environments and mission‑critical infrastructure.

This is a highly technical role for a Linux security specialist who enjoys solving complex system challenges and working in advanced secure environments.

Locations: Littleton, CO
• King of Prussia / Valley Forge, PA
• Herndon, VA
• Springfield, VA

• Serve as a Subject Matter Expert (SME) for SELinux and Multi‑Level Security (MLS) configurations across enterprise Linux environments
• Support secure Linux environments for enterprise systems and High Performance Computing (HPC) infrastructure
• Configure and maintain SELinux policies, security contexts, MAC labeling, and least‑access policies
• Troubleshoot and debug SELinux policy and kernel‑level issues using system logs and debugging tools
• Develop and maintain secure MLS configurations, including MLS FreeIPA and secure networking configurations
• Write and maintain automation and operational scripts using Bourne/Bash and Expect
• Manage Linux patching and repository management using Satellite Server
• Build and maintain custom Linux kernels to meet functionality and security requirements
• Implement automation for configuration and patching using Ansible and Satellite Server
• Support and maintain identity and access management systems, including LDAP and token‑based authentication
• Collaborate with engineering and infrastructure teams to ensure systems remain secure, compliant, and highly available

• Active TS/SCI with CI Polygraph (required to start)
• Bachelor's degree in Computer Science, Information Systems, or related field
• 10+ years of experience in Linux systems administration or related technical roles
• At least 5 years of experience working in heterogeneous, multi‑platform computing environments
• Deep expertise with SELinux configuration and Multi‑Level Security (MLS) environments
• Experience with:
• SELinux policies and policy debugging
• Mandatory Access Control (MAC) labeling
• Security contexts
• Developing least‑access policies
• MLS FreeIPA configurations
• MLS Ethernet interface networking
• Proficiency in Bourne/Bash and Expect scripting
• Experience debugging Linux kernel issues, including analyzing system logs and source code
• Experience using Linux debugging tools such as crash and systemtap
• Experience managing Satellite repositories for patching and kernel management
• Familiarity with Ansible and Satellite Server for configuration and patch automation
• Experience working with identity management systems, including LDAP and token‑based authentication

• Experience supporting High Performance Computing (HPC) environments
• Experience supporting enterprise MLS or cross‑domain solutions
• Familiarity with large‑scale Linux infrastructure in classified environments
• Experience improving automation, security, and system reliability across enterprise platforms