Senior Linux SME: Cross-Domain Security & Automation

DAn Solutions, Inc; Bethesda (MD); On-site; USD 140,000 - 190,000; Full time

Job summary

DAn Solutions, Inc. seeks an experienced Linux Subject Matter Expert (SME) to provide advanced systems engineering and operational support for Cross Domain Shared Services Framework within a secure DIA environment.

Embedded with the CDS team, you will maintain, harden, troubleshoot, and optimize Linux systems across multiple domains and mission enclaves. The role requires deep knowledge of RHEL, STIG hardening, cross-domain security architectures, and RMF/ATO processes essential for TS/SCI

Qualifications

• U.S. Citizen with active TS/SCI clearance and CI Polygraph (or ability to obtain).
• 8+ years Linux administration in a secure, mission-critical environment.
• 3+ years cross-domain or multi-enclave experience (CDS, Garrison, SMART.NeXT, CDSSF).
• Advanced knowledge of RHEL 7/8/9, system hardening, and kernel tuning.
• Automation frameworks and scripting (Ansible, Bash, Python).
• RMF/ATO processes and audit log management.
• Networking knowledge relevant to Linux (TCP/IP, firewalls, DNS).

Responsibilities

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

Skills

Linux sysadmin

System hardening

Automation scripting

Python

Bash scripting

Performance troubleshooting

Security compliance

Education

DoD 8570 IAT Level II/III

RHCE

Security+ CE

CISSP

CASP+

Tools

Ansible

SCAP

Puppet

VMware

KVM

Splunk

Job description

DAn Solutions, Inc. seeks an experienced Linux Subject Matter Expert (SME) to provide advanced systems engineering and operational support for Cross Domain Shared Services Framework within a secure DIA environment.

Embedded with the CDS team, you will maintain, harden, troubleshoot, and optimize Linux systems across multiple domains and mission enclaves. The role requires deep knowledge of RHEL, STIG hardening, cross-domain security architectures, and RMF/ATO processes essential for TS/SCI