Senior Information Systems Security Engineer (ISSE)

Vista Government Solutions (VGS) is seeking a Senior Information Systems Security Engineer (ISSE) to support the Uniformed Services University Health Sciences (USUHS) Network Operations Center Cyber Support Services Task Order. The Senior Information Systems Security Engineer (ISSE) provides technical cybersecurity and Risk Management Framework (RMF) support for the rewrite and modernization of the Agency's Office 365 (O365) Authorization to Operate (ATO) package. The ISSE evaluates existing authorization documentation, technical configurations, system architecture, security-control implementation, and supporting evidence to develop accurate, complete, and eMASS-ready RMF artifacts. NOC Cyber_PD SR ISSE The ISSE works in coordination with the Government ISSM and technical stakeholders to ensure that security documentation accurately reflects the implemented O365 environment and applicable DoD and NIST cybersecurity requirements. The Government ISSM retains responsibility for cybersecurity governance, formal risk management oversight, and coordination with the authorization chain. NOC Cyber_PD SR ISSE

What You’ll Do:

• Provide oversight and technical guidance to MS InTune and SCCM Endpoint Engineers.
• Support the comprehensive rewrite and modernization of the Agency's O365 ATO package and associated eMASS documentation.
• Review existing RMF and Information Assurance documentation to identify outdated, incomplete, duplicative, or technically inaccurate information.
• Develop and update System Security Plan (SSP) content, security-control implementation statements, POA&M documentation, inheritance mappings, system diagrams, and other required authorization artifacts.
• Analyze applicable NIST SP 800-53 controls, DoD security requirements, DISA guidance, and inherited enterprise controls to determine documentation and evidence requirements.
• Review Microsoft 365/O365 configurations and supporting technical artifacts to determine how security controls are implemented within the operational environment.
• Coordinate with Microsoft 365 engineers, system administrators, endpoint engineers, cybersecurity personnel, and other technical SMEs to collect and validate information required for the ATO package.
• Review technical evidence and supporting artifacts for completeness, consistency, traceability, and alignment with documented security-control implementation.
• Document applicable Identity, Credential, and Access Management (ICAM), endpoint security, encryption, continuous monitoring, and Zero Trust capabilities as they relate to the O365 authorization boundary.
• Identify documentation and evidence gaps and coordinate with appropriate technical stakeholders to support resolution.
• Support development and maintenance of POA&Ms and associated remediation documentation for identified deficiencies. NOC Cyber_PD SR ISSE
• Utilize eMASS to develop, update, organize, and maintain authorization artifacts and supporting evidence.
• Support the Government ISSM in preparing the O365 authorization package for review by applicable cybersecurity and authorization stakeholders.
• Address technical documentation deficiencies, questions, and comments identified during Government review of the authorization package.
• Support development of a technically accurate, complete, traceable, and submission-ready O365 ATO package.
• Maintain configuration, documentation, and evidence traceability throughout the ATO rewrite effort.
• Support knowledge transfer and development of repeatable processes for maintaining authorization documentation following completion of the rewrite. NOC Cyber_PD SR ISSE

What You Bring:

Required:

• Active Secret clearance.
• Security+ or higher certification.
• Bachelor's degree in Cybersecurity, Information Technology, Systems Engineering, Computer Science, or a related technical discipline, or equivalent combination of education and relevant experience.
• Approximately 7–10 years of progressive experience in cybersecurity, information assurance, systems security engineering, RMF, or related disciplines.
• Demonstrated experience developing or maintaining RMF authorization packages within DoD or other federal environments.
• Working knowledge of NIST SP 800-53 security controls and RMF processes.
• Experience developing and reviewing SSPs, security-control implementation statements, POA&Ms, inheritance documentation, system architecture information, and supporting authorization evidence.
• Experience with eMASS or a comparable Governance, Risk, and Compliance (GRC) platform.
• Ability to analyze technical configurations and translate technical implementation into accurate security-control documentation.
• Familiarity with Microsoft 365/O365 enterprise environments and associated security capabilities.
• Experience working collaboratively with ISSMs, system owners, engineers, administrators, and cybersecurity personnel.
• Strong technical writing, analytical, documentation, and communication skills. NOC Cyber_PD SR ISSE

Preferred:

• Microsoft security certifications such as SC-100, SC-200, AZ-500, or equivalent Microsoft 365/Azure security credentials are highly desirable. NOC Cyber_PD SR ISSE

What We Offer:

Vista Government Solutions (VGS) offers a competitive benefits package to include: paid holidays, paid time off including sick and vacation leave, medical, dental and vision insurance, flexible spending accounts, short and long term disability, company paid life insurance, 401(k) with a company match and discretionary profit sharing and tuition reimbursement.