Information System Security Engineer​/Systems Admin; SA​/ISSE - TS​/SCI CI Polygraph

TITLE: Information System Security Engineer / Systems Admin (SA/ISSE)

LOCATION: McLean, VA

CLEARANCE REQUIRED: Active DoD TS/SCI with CI Polygraph

EMPLOYMENT TYPE: Full-time, On-site

Modern Government Solutions (MGS) is seeking an Information Systems Security Engineer (ISSE) with System Administrator (SA) experience to support the design, implementation, and accreditation of secure systems for mission‑critical government programs. The SA/ISSE will ensure security is embedded throughout the system lifecycle by applying Risk Management Framework (RMF) principles, implementing technical controls, and developing security documentation in compliance with DoD and federal cybersecurity standards.

Specific responsibilities include fielding, accrediting and maintaining a Top Secret Contractor Wide Area Network (CWAN).

The ideal candidate brings hands‑on experience with system hardening, vulnerability management, and ATO processes in NRO-sponsored CWAN infrastructure, along with the ability to collaborate effectively across technical and program teams in classified environments.

• Integrate security controls into system architectures and engineering designs to ensure compliance with DoD and federal cybersecurity requirements.
• Develop, maintain, and review security documentation including System Security Plans (SSPs), Security Assessment Reports (SARs), POA&Ms, and related RMF artifacts.
• Conduct and support security assessments, vulnerability scans, and risk analyses to identify and mitigate potential weaknesses.
• Coordinate with system administrators, developers, and network engineers to implement technical security controls and ensure ongoing compliance.
• Support security authorization and accreditation (A&A) processes to achieve and maintain Authority to Operate (ATO).
• Participate in design reviews, configuration management boards, and change control processes to ensure security implications are properly addressed.
• Provide security engineering input to system design, architecture decisions, and testing activities.
• Collaborate with ISSOs, ISSMs, and government security officials to meet program security objectives and milestones.
• Stay current with evolving federal cybersecurity guidance, tools, and threat trends.

• Must possess an active Department of Defense (DoD) TS/SCI with CI Polygraph security clearance.
• Bachelor's degree in Computer Science, Information Systems, Cybersecurity, Engineering, or related field.
• 5+ years of experience in systems or network security engineering within a federal or DoD environment.
• Strong understanding of the Risk Management Framework (RMF) and associated documentation.
• Hands‑on experience with system hardening, vulnerability management, and security control implementation on Linux and/or Windows platforms.
• Working knowledge of NIST 800‑53, CNSSI 1253, DoD 8510.01, and FISMA standards.
• Proficiency with common security tools such as ACAS, Nessus, STIG Viewer, or SCAP.
• Demonstrated experience managing POA&Ms through identification, remediation, and closure of security findings to support RMF and ATO compliance.
• Strong communication and documentation skills for preparing technical reports and security artifacts.
• Ability to collaborate across multidisciplinary technical teams and engage with government stakeholders.

• Direct experience implementing, accrediting and/or maintaining NRO-sponsored CWAN infrastructure.
• DoD 8570 IAT Level II/III or IAM Level II/III certification (e.g., Security+, CISSP, CISM, CASP).
• Experience supporting the NRO RMF and RMF‑based ATO processes for classified or cloud‑based environments.
• Familiarity with Secure Dev Ops/Dev Sec Ops  pipelines and automation tools.
• Experience supporting DoD, IC, or other federal mission systems.
• Master's degree in Cybersecurity, Systems Engineering, or a related technical discipline.

Applicants selected will be United States citizens and may be subject to a government security investigation for access to classified information.

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