Senior ISSE - RMF Security Engineer (TS/SCI + Poly)

System One; Clarksburg (MD); On-site; USD 162,000 - 198,000; Full time

Job summary

System One in Clarksburg, MD seeks an Information Systems Security Engineer (ISSE) to support mission-critical, classified systems. You will apply cybersecurity engineering best practices across design, implementation, authorization, and ongoing compliance.

Hands-on with RMF, A&A, ATO sustainment, and vulnerability/stig compliance efforts, you will collaborate with security and technical teams to build secure, auditable systems and continuous monitoring processes.

Qualifications

• Active TS/SCI clearance is required.
• DoD 8570/8140 IASAE Level II compliant certification is required.
• Strong RMF knowledge and A&A/ATO experience.
• Experience implementing security controls and continuous monitoring.
• Familiarity with NIST SP 800-37 and SP 800-53.
• Experience with RMF/cybersecurity tools.

Responsibilities

• Support full RMF lifecycle for classified systems from planning through continuous monitoring.
• Contribute to A&A packages and maintain ATOs over time.
• Implement, assess, and validate security controls and requirements.
• Build and maintain RMF documentation and evidence artifacts.
• Define system boundaries and document security architecture.
• Run and analyze compliance scans and validate results.
• Support STIG implementation, hardening, remediation verification, and patch validation.
• Participate in Continuous Monitoring activities and reporting.

Skills

Active TS/SCI clearance

RMF knowledge

A&A experience

Documentation skills

NIST SP 800-37/53 familiarity

Security compliance tools familiarity

Tools

LATTEART

XACTA

BISCOTTI

WATCHCAT

STE

Job description

System One in Clarksburg, MD seeks an Information Systems Security Engineer (ISSE) to support mission-critical, classified systems. You will apply cybersecurity engineering best practices across design, implementation, authorization, and ongoing compliance.

Hands-on with RMF, A&A, ATO sustainment, and vulnerability/stig compliance efforts, you will collaborate with security and technical teams to build secure, auditable systems and continuous monitoring processes.