Sr. Cybersecurity Engineer (ISSE / Product Security Engineering)

Istari Digital; United States; On-site; USD 90,000 - 120,000; Full time

Benefits offered by this job

Possible stipend for clearance

One-time incentive

Job summary

A digital engineering firm in the United States seeks an Information System Security Engineer to implement cybersecurity measures directly within their platform. The role involves applying security controls, leading system hardening, and securing data pipelines. Ideal candidates will have 5+ years of hands-on experience in cybersecurity and an active TS clearance with SCI eligibility. This position offers opportunities to work in classified environments, emphasizing practical security implementations in a startup atmosphere.

Qualifications

• 5+ years in cybersecurity with hands-on implementation experience.
• DoD 8570/8140 certification (Security+ minimum; CISSP/CASP+/CISM preferred).
• Active TS clearance with SCI eligibility required.

Responsibilities

• Implement NIST 800-53 / 800-171 security controls directly into system design.
• Lead system hardening and secure configuration across platform components.
• Partner with teams to secure APIs, services, and data pipelines.

Skills

NIST 800-53 / 800-171 security controls implementation

System hardening

DevSecOps

Vulnerability scanning (ACAS/Nessus)

POA&M management

API security

Tools

Nessus

ACAS

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.

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, and 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 and high‑level security architecture decisions
• 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

We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.

(may be additionally eligible for stipend, one‑time incentive, or % differential for clearance)