Senior Information Systems Security Engineer (ISSE)

Senior Information Systems Security Engineer (ISSE)Location: Stennis Space Center, MS (On-Site at CNMOC Headquarters) Clearance Required: Active TS/SCI Position Type: Full-Time Period of Performance: One-Year Task Order Position OverviewLATG is seeking an experienced Senior Information Systems Security Engineer (ISSE) to support Cross Domain Solution (CDS) cybersecurity and Risk Management Framework (RMF) accreditation efforts within the Intelligence Community (IC) environment. This position will lead the migration and management of RMF packages utilizing Xacta 360 and support accreditation activities for mission-critical systems operating on the Joint Worldwide Intelligence Communications System (JWICS).The ideal candidate possesses extensive hands-on RMF experience supporting Intelligence Community organizations and has successfully managed system accreditation packages within Xacta 360 (formerly Xacta IA Manager). The candidate will serve as a trusted cybersecurity advisor, working directly with government stakeholders to ensure compliance with IC security requirements, NIST controls, and authorization processes.This role requires an individual who can independently manage accreditation efforts, coordinate with Authorizing Officials and cybersecurity teams, and drive RMF package completion from initiation through authorization. What You'll Be DoingThe Senior ISSE will provide cybersecurity engineering and RMF accreditation support for mission-critical systems operating within classified environments.Key ResponsibilitiesLead the development, maintenance, and submission of RMF authorization packages using Xacta 360.Support migration of existing Cross Domain Solution (CDS) accreditation packages into the Xacta framework.Develop, maintain, and update System Security Plans (SSPs), security control assessments, POA&Ms, and supporting RMF artifacts.Interpret and apply Intelligence Community (IC) security overlays and cybersecurity requirements.Ensure compliance with NIST SP 800-53 Rev. 4 and Rev. 5 security controls.Support accreditation activities for systems operating within JWICS environments.Coordinate with government cybersecurity personnel, Authorizing Officials, Security Control Assessors, and mission stakeholders.Conduct security control implementation reviews and validation activities.Analyze vulnerabilities, document mitigation strategies, and support corrective action efforts.Participate in cybersecurity reviews, inspections, audits, and authorization activities.Provide technical security guidance throughout the system lifecycle.Develop and maintain cybersecurity documentation and accreditation records.Support transition of completed RMF packages to government personnel for ongoing maintenance and management. What You'll BringThe ideal candidate will possess extensive RMF experience supporting Intelligence Community organizations, strong knowledge of classified network security requirements, and demonstrated expertise using Xacta for system authorization packages.Required QualificationsBachelor's degree in Cybersecurity, Information Technology, Computer Science, Information Systems, Engineering, or related field. Equivalent experience may be substituted.Minimum of five (5) years of direct hands-on experience utilizing Xacta 360 or Xacta IA Manager to prepare, manage, and process RMF authorization packages.Experience supporting RMF accreditation efforts within Intelligence Community environments.Strong understanding of:RMF processes and lifecycle activitiesIntelligence Community cybersecurity requirementsJWICS security requirementsCDS accreditation processesNIST SP 800-53 Rev. 4 and Rev. 5 controlsSecurity assessment and authorization activitiesExperience developing RMF documentation including SSPs, SARs, Security Control Traceability Matrices, and POA&Ms.Strong analytical, problem-solving, communication, and documentation skills.Ability to work independently with minimal supervision in a mission-focused environment.Security RequirementsActive Top Secret clearance required.Current SCI eligibility or active SCI access required.Must be able to maintain TS/SCI eligibility throughout employment. Preferred QualificationsCISSP certification.CASP , Security , or equivalent DoD 8570/8140 cybersecurity certification.Experience accrediting Cross Domain Solutions (CDS).Knowledge of Intelligence Community Directive (ICD) cybersecurity requirements.Experience supporting Department of Defense or Intelligence Community organizations.Experience working directly with Security Control Assessors (SCAs) and Authorizing Officials (AOs).Familiarity with automated GRC tools and cybersecurity compliance platforms. Work LocationThis position is performed on-site at CNMOC Headquarters, Stennis Space Center, Mississippi. Regular on-site presence is required due to the classified nature of the work and access to secure facilities.