Linux Subject Matter Expert (SME)

We are seeking an experienced Linux Subject Matter Expert (SME) to provide advanced systems engineering and operational support for CDSSF Cross Domain Shared Services Framework within a secure Defense Intelligence Agency (DIA) environment. This role is embedded with our Cross Domain Solutions (CDS) team and is responsible for maintaining, hardening, troubleshooting, and optimizing Linux-based systems across multiple domains and mission enclaves.

The ideal candidate will have a deep understanding of Red Hat Enterprise Linux (RHEL), system hardening (STIG), cross domain security architectures, and the accreditation processes necessary to support Top Secret/Sensitive Compartmented Information (TS/SCI) systems.

Key Responsibilities

• Lead system engineering, patching, configuration, and lifecycle maintenance of RHEL/CentOS/Oracle Linux systems supporting CDS environments.
• Implement and maintain DISA STIG-compliant baselines using automation tools (e.g., Ansible, SCAP, Puppet).
• Collaborate with CDS engineers, Information Assurance personnel, and enclave leads to meet ATO/RMF compliance.
• Troubleshoot kernel-level issues, performance bottlenecks, and cross-domain interface stability.
• Provide SME-level support for SE Linux, LDAP/Kerberos, and auditing solutions (e.g., syslog, Splunk forwarders).
• Manage OS provisioning, virtual infrastructure (e.g., VMware or KVM), and baseline image creation for cross-domain enclaves.
• Assist with developing and maintaining infrastructure-as-code configurations and custom scripts (Bash, Python).
• Serve as Tier III escalation for complex OS issues affecting CDS reliability or availability.
• Support enclave isolation and guard-side interface requirements under strict security policies.
• Document engineering decisions, operational procedures, and system configurations for cross-team knowledge sharing and accreditation packages.

• U.S. Citizen with active TS/SCI clearance and CI Polygraph (or ability to obtain).
• 8+ years of experience administering Linux systems in a secure, mission-critical environment.
• 3+ years supporting cross-domain or multi-enclave environments (CDS, Garrison, SMART.NeXT, CDSSF).
• Advanced knowledge of RHEL 7/8/9, including system hardening and kernel-level tuning.
• Experience with automation frameworks and scripting languages (Ansible, Bash, Python).
• Familiarity with RMF/ATO processes and audit log management.
• Strong understanding of networking (TCP/IP, firewalls, VLANs, DNS) as it relates to Linux systems.

• DoD 8570 IAT Level II or III certification (Security+ CE, CASP+, CISSP).
• Red Hat Certified Engineer (RHCE) or similar Linux certification.
• Familiarity with CDS guard technologies (Radiant Mercury, Data Diode, Garrison, etc.).
• Experience with hypervisors and virtual infrastructure supporting isolated environments.
• Knowledge of Zero Trust, enclave segmentation, and compartmentalized architectures.