Information System Security Engineer

TITLE: Information System Security Engineer (ISSE) LOCATION: Sterling, VA CLEARANCE REQUIRED: Active DoD TS/SCI with CI Polygraph EMPLOYMENT TYPE: Full-time, On-site POSITION SUMMARY Modern Government Solutions (MGS) is seeking an Information Systems Security Engineer (ISSE) to support the design, implementation, and accreditation of secure systems for mission-critical government programs. The 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. The ideal candidate brings hands-on experience with system hardening, vulnerability management, and ATO processes, along with the ability to collaborate effectively across technical and program teams in classified environments. RESPONSIBILITIES 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. REQUIRED SKILLS AND QUALIFICATIONS 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 , 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. PREFERRED SKILLS AND QUALIFICATIONS 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. Experience supporting RMF-based ATO processes for classified or cloud-based environments. Familiarity with Secure DevOps/DevSecOps 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.* ABOUT US At MGS, we believe a people-first culture corresponds to organizational success through a commitment to excellence, integrity, inclusion, and an attitude that welcomes challenges meets demands, sustains growth, and drives innovation. We provide expert mission-first technical and programmatic services and solutions for the US intelligence community, the US Department of Defense, and other governmental agencies. We create people-first organizational cultures where employees feel needed in the system, not a system that needs employees. We provide you with long-term career opportunities centrally focused on our core value system: inclusion, integrity, and a commitment to excellence. MGS is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, or protected veteran status, and will not be discriminated against on the basis of disability. #J-18808-Ljbffr