Cybersecurity Engineer – Classified Infrastructure (Customer Success) at Istaridigital.ai

Security Clearance: Active TS required with SCI eligibility (Polygraph a plus) About Istari Digital Istari Digital delivers a model-based digital engineering platform used by defense and aerospace organizations to design and operate mission-critical systems. Our platform is deployed into classified and high-security environments, where cybersecurity is foundational—not optional. Role Overview We are hiring a Cybersecurity Engineer to support customer deployments in classified environments, ensuring Istari’s platform operates securely, compliantly, and reliably in real-world mission systems. This role sits within Customer Success and focuses on hands-on system and infrastructure security—not just documentation or policy. Depending on your background, you may lean more toward: System hardening (Windows/Linux) Secure network infrastructure (classified environments) In this role YOU will be the difference between a platform that looks secure on paper, and one that actually works inside real classified mission environments. What You'll Do • Deploy and secure Istari’s platform in: • SIPR, JWICS, and air-gapped environments • Implement and validate: • DISA STIGs • NIST 800-53 / 800-171 controls • Perform hands-on security work, including: • System hardening (Windows & Linux) • Vulnerability scanning (ACAS/Nessus) • STIG validation and remediation • POA&M management • Design, configure, or support secure network architectures, including: • Segmentation, boundary defense, and routing in classified environments • Troubleshoot and resolve: • Security configuration issues • Connectivity and compliance blockers • Work directly with: • Customer security teams (ISSO, ISSM, AO, SCA) • Program and infrastructure teams • Provide feedback to engineering on: • Real-world deployment constraints • Security gaps and improvements Required Qualifications Must-Haves • Active TS clearance with SCI eligibility Security+ (required) — CISSP, CISM, or CASP+ preferred • 4+ years of hands-on experience in cybersecurity, system administration, or network engineering • Direct experience with: • NIST 800-53 / 800-171 • DISA STIGs • Experience operating in: • Classified environments (SIPR, JWICS, SAP) Your Background (You may come from one or both areas) Experience Profile A: System Hardening (System Administration) • Strong experience securing: • Windows and/or Linux systems • Hands-on System Patching, STIG implementation and validation • Experience running scans, remediating findings, and managing POA&Ms Experience Profile B: Secure Infrastructure (Network Engineering) • Experience designing or supporting: • Secure network architectures in classified environments • Knowledge of: • Network segmentation, boundary defense, and secure connectivity • Familiarity with STIGs for network devices and infrastructure What Makes You a Strong Fit • You started in a technical role (SysAdmin, Network, SOC) and moved into security • You’ve done real, hands-on work—not just compliance oversight • You’re comfortable working: • In deploying emerging technology into real-world classified environments • Under time pressure to meet deployment or mission deadlines • You stay long enough to see systems through deployment and accreditation • You’re comfortable in a startup environment—scrappy, fast-moving, and collaborative • You’re willing to do the work needed to get across the finish line, even when it’s manual