Sr. Cybersecurity Engineer (ISSE / Product Security Engineering)
About the Job
- Posted on
- Mar 18, 2026
- Apply before
- Apr 17, 2026
- Job type
- Full-Time
- Location
- Worldwide
Job Description
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.
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
Ready to apply?
This position is 100% remote — work from anywhere in the world.