Information System Security Engineer

Leidos is seeking an Information System Security Engineer (ISSE) to support cybersecurity authorization related efforts for SMIT. SMIT is the largest IT services program for the Navy. Under the Service Management, Integration, and Transport (SMIT) program, the Leidos team will deliver the core backbone of the Navy's enterprise network (NMCI), including cybersecurity services, network operations, service desk, and data transport. Ultimately, the Leidos team will support the Navy in unifying its shore-based networks and data management to improve capability and service while also saving significant dollars by focusing efforts under one enterprise network. Primary Responsibilities: The ISSE will perform cybersecurity authorization services, including acting as a main point of contact for cybersecurity authorization related aspects to the assigned information systems, ensuring systems are maintained per security policies and procedures and maintaining compliance and ongoing reporting to management. Responsibilities include: Serve as a primary information system security engineer (ISSE) for Authorization to Operate (ATO) packages under the Navy Risk Management Framework (RMF) Assist in the development and review of ATO submissions and coordinate all updates and corrections to assessment and authorization (A&A) artifacts Evaluate software and hardware during pre-acquisition phases to determine its ability to meet minimum security requirements based on NIST SP 800-53 Rev 5 security controls. Author, review, coordinate and submit cybersecurity authorization required artifacts to eMASS (including change requests) to achieve milestones such as Interim Authority to Test (IATT) and ATO in accordance with the project schedule. Support conducting cybersecurity authorization activities to comply with all current Cybersecurity and IA manuals, instructions, and guides within the DoDI 8500.01, DON 5239, the RMF Process Guide, and the RMF Risk Assessment Guide. Continuously monitor system resources through automated scanning and implement automated reporting feeds to support cybersecurity authorizations Verify patch compliance using the approved technical solution (i.e., Assured Compliance Assessment Solution (ACAS)), Information Assurance Vulnerability Alert (IAVA) compliance dashboards, and Microsoft Defender for Endpoints. Coordinate with local administrators to troubleshoot and elevate patching issues in a timely manner in order to meet patch compliance timelines. Assist with the implementation of security procedures, and verify information system security requirements, including coordinating the execution, review, and disposition of Security Technical Implementation Guide (STIG) checklists for systems, applications, developed code and other components. Independently develop and maintain system security documentation, including drafting, reviewing, editing and recommending guidance for Standard Operating Procedures (SOP), Tactics, Techniques, & Procedures (TTP), Plan of Action and Milestones (POA&M) and Federal Information Security Management Act (FISMA) Score Card. Participate in regular briefings with the customer on cybersecurity statuses, including preparing briefing materials. Work closely with government Cyber team to support ATO conditions and requirements Support site visits / audits, including System Readiness Reviews (SRR) Ensure secure, effective and efficient operation of network systems, architecture, and topology Assist with the development and application of business processes to ensure they have the appropriate level of security Participate in strategic network, security, and operations new technology planning As a cybersecurity authorization services security expert, assist the engineering managers in employing approved defense-in-depth principles and practices (e.g., defense-in-multiple places, layered defenses, and security robustness) Discuss and document the Ports, Protocols and Services (PPS) to include ensuring the dataflows are accurate, CAL boundaries crossed are compliant, and registrations with the AO are completed per DODI 8551.1 Basic Qualifications: US Citizen and DoD Secret Clearance Hold an active security certification that meets DOD 8570 IAT level III or higher Bachelor's degree and 4 years of prior relevant experience or Master's with 2 years of prior relevant experience in Cybersecurity, Information Security, IT, EE, Network Engineering, Computer Science, or related field. Must have complete understanding of the RMF steps, especially Steps 4 through Steps 7 Ability to identify upon review of a system authorization boundary and its components to identify all applicable STIGs Ability to decompose a security control/security check and ensure the provided artifact and test result satisfies said control/AP/check Understanding of techniques and tactics used to exploit systems (MITRE ATTACK) to determine risk and possible mitigations Ability to understand technical mitigations/know resources to identify proper mitigating factors (i.e. ) Experience with eMASS to include control inheritance, TR Import, and POAM import functionality. Support conducting cybersecurity authorization activities to comply with all current Cybersecurity and IA manuals, instructions, and guides within the DoDI 8500.01, DON 5239, the RMF Process Guide, and the RMF Risk Assessment Guide. Verify patch compliance using the approved technical solution (i.e., Assured Compliance Assessment Solution (ACAS)), Information Assurance Vulnerability Alert (IAVA) compliance dashboards, and Microsoft Defender for Endpoints. Assist with the implementation of security procedures, and verify information system security requirements, including coordinating the execution, review, and disposition of Security Technical Implementation Guide (STIG) checklists for systems, applications, developed code and other components. Independently develop and maintain system security documentation, including drafting, reviewing, editing and recommending guidance for Standard Operating Procedures (SOP), Tactics, Techniques, & Procedures (TTP), Plan of Action and Milestones (POA&M) and Federal Information Security Management Act (FISMA) Score Card. Assist with the development and application of business processes to ensure they have the appropriate level of security Discuss and document the Ports, Protocols and Services (PPS) to include ensuring the dataflows are accurate, CAL boundaries crossed are compliant, and registrations with the AO are completed per DODI 8551.1 Hands-on experience with a variety of cybersecurity tools. Hands-on experience in working with DoD networks. Experience in FISMA and other information assurance assurance-related compliance reporting. Attention to detail is a must Ability to multi-task, self-assign work in a dynamic, fast-paced environment. Analytical, communication and troubleshooting skills that enable proactive and effective collaboration with a virtual team, including the ability to clearly articulate status and present to both customers and program leadership. Experience in one of the following areas: cybersecurity assessment, vulnerability scanning, integration and testing, data analytics or security operations. Experience leading cybersecurity tasks and collaborate with customers, stakeholders, and team members Knowledge of cybersecurity assessment and authorization (A&A) and associated processes, procedures, and activities in accordance with DoDID 8500.01, DoDI 8551.01, the RMF Process Guide, the RMF Risk Assessment Guide, and other applicable NIST instructions, guidelines. Experience supporting the formal Cybersecurity/IA testing required by government accrediting authorities and preparing System Security Plans. Communication abilities, both verbal and written, including business writing on complex topics. Able to reach out across different teams and disciplines to include internal/external stakeholders Understanding of supporting security initiatives, conducting security monitoring, reporting and maintaining security compliance following security regulations and policies. Knowledge of Security Engineering and Architecture, Assessment and Authorization, Vulnerability Assessment, Incident Management, Vulnerability Management, Security Operations, and Policy and Program Development Motivated self-starter with ability to lead and work in a matrix organization and communicate effectively with peers and program leadership Preferred Qualifications: Top Secret Clearance Hands-on experience in working with Cloud Authorizations Hands-on experience in working with NMCI authorizations Experience with ITIL processes and/or ITIL Foundation V4 certification An entrepreneurial spirit with the ability to drive innovation independently; have a passion to improve at every opportunity Proven ability to credibly coordinate between technical teams and business stakeholders Willing to perform shift work NGEN If you're looking for comfort, keep scrolling. At Leidos, we outthink, outbuild, and outpace the status quo — because the mission demands it. We're not hiring followers. We're recruiting the ones who disrupt, provoke, and refuse to fail. Step 10 is ancient history. We're already at step 30 — and moving faster than anyone else dares. Original Posting: August 19, 2026 For U.S. Positions: While subject to change based on business needs, Leidos reasonably anticipates that this job requisition will remain open for at least 3 days with an anticipated close date of no earlier than 3 days after the original posting date as listed above. Pay Range: Pay Range $87,100.00 - $157,450.00 The Leidos pay range for this job level is a general guideline only and not a guarantee of compensation or salary. Additional factors considered in extending an offer include (but are not limited to) responsibilities of the job, education, experience, knowledge, skills, and abilities, as well as internal equity, alignment with market data, applicable bargaining agreement (if any), or other law.