Sr. Cybersecurity Engineer (ISSE / Product Security Engineering) at Istaridigital.ai

Security Clearance: Active TS required with SCI eligibility (Poly preferred) Istari Digital delivers a model-based digital engineering platform that enables defense and aerospace teams to design, integrate, and operate complex systems. Our platform operates in classified, mission-critical environments, where cybersecurity must be engineered into the system—not bolted on. Role Overview We are hiring an Information System Security Engineer (ISSE) to serve as the technical implementer of cybersecurity within our platform.  This is not a policy or compliance role.  You will take security requirements (RMF, NIST, customer constraints) and directly apply them to system architecture, infrastructure, and the software development lifecycle. What You'll Do • Implement NIST 800-53 / 800-171 security controls directly into system design and platform architecture • Lead system hardening and secure configuration across platform components • Embed security into the engineering workflow (DevSecOps) • Perform: • System Patching • STIG implementation and validation • Vulnerability scanning (ACAS/Nessus) • POA&M management and remediation tracking • Partner with engineering teams to: • Secure APIs, services, and data pipelines • Enforce least privilege, identity, and access controls • Support deployment into: • SIPR / JWICS / SAP environments • Identify and remediate security gaps before they reach customer environments Required Qualifications • Active TS clearance with SCI eligibility • DoD 8570/8140 certification (Security+ minimum; CISSP/CASP+/CISM preferred) • 5+ years in cybersecurity with hands-on implementation experience • Direct experience with: • NIST 800-53 / 800-171 • DISA STIGs • ACAS/Nessus • Background in: • Systems Administration, Network Engineering, or SOC → transitioned into security • Experience working in: • Classified environments (SIPR, JWICS, SAP) What Makes You a Strong Fit • You’ve actually hardened systems—not just documented controls • You can move between: • Low-level system configuration • High-level security architecture decisions • You are comfortable doing manual, in-the-weeds work when needed to hit deadlines • Track record of stability (2+ years per role preferred) • Comfortable in a startup environment • Willing to own problems end-to-end, not just your lane