Information System Security Engineer

Leidos LLC; San Diego (CA); On-site; USD 108,000 - 195,000; Full time

Benefits offered by this job

Health insurance

Paid Leave and Retire

Retirement benefits

Job summary

Leidos is seeking an Information System Security Engineer to support classified information systems and collaborate with program teams in San Diego. The role emphasizes securing, maintaining, and supporting complex environments while ensuring compliance with security protocols and regulations.

The ISSE will work on full-system lifecycle activities, design secure architectures, and mentor junior staff. A TS clearance and SCI eligibility post hire are required, with onsite work at Campus Point in

Qualifications

• Active Top Secret clearance required and eligible for SAP/SCI post hire.
• Bachelor's degree or equivalent experience with 8–12 years, or Master’s with 6–10 years or certifications in lieu of degree.
• Hands-on experience administering, engineering, or securing Windows and Linux servers.
• Experience implementing RMF and JSIG controls across systems.
• Ability to interpret cybersecurity requirements and translate into configurations and deployments.

Responsibilities

• Protect information and maintain security controls for systems, sites, or programs.
• Serve as ISSE for SAP information systems across full system lifecycle.
• Design and maintain secure classified information systems and architectures per JSIG and RMF.
• Develop secure configurations, baselines, and automation to improve compliance.
• Support government security assessments, authorization reviews, and audits.

Skills

Top Secret clearance

RMF knowledge

JSIG knowledge

Windows/Linux administration

Virtualization

Nessus

Documentation skills

Education

Bachelor's degree or equivalent experience

Tools

DISA STIGs

SRGs

Active Directory

Group Policy

Splunk

Job description

Leidos' Corporate Information Security Office, reporting through the Digital Sector, is seeking an Information System Security Engineer to support various information systems and act as the Subject Matter Expect to Junior System Administrators. The successful candidate will be responsible for maintaining, securing, and supporting complex classified information systems, as well as ensuring compliance with security protocols and regulations.

Location: This position is full time, onsite at our Campus Point, San Diego office.

Clearance: You must currently hold an active DoD Top Secret clearance to be considered and must be eligible to obtain Special Access Program and Special Compartmented Access (SCI) post hire.

Primary Responsibilities

• This role includes a combination of duties to protect information, and maintain security controls, for an entire system, site, or program to reduce risk.


• Serve as the Information System Security Engineer (ISSE) for Special Access Program information systems, providing security engineering support throughout the full system lifecycle from research and development through deployment, accreditation, operations, maintenance, and decommissioning.


• Design, develop, integrate, and maintain secure classified information systems and architectures in accordance with the Joint Special Access Program Implementation Guide (JSIG), Risk Management Framework (RMF), applicable DoW policies, and program-specific security requirements.


• Develop and maintain system security architecture, including network segmentation, boundary protections, authentication, privileged access, encryption, auditing, logging, secure communications, virtualization, storage, and data protection solutions.


• Implement and validate DISA Security Technical Implementation Guides (STIGs), Security Requirements Guides (SRGs), vendor security guidance, and program specific hardening requirements across Windows, Linux, network, virtualization, storage, and supporting infrastructure.


• Coordinate with ISSMs, ISSOs, System Administrators, and Program Management to resolve technical and compliance issues.


• Develop secure configuration baselines, build procedures, automation, scripts, and configuration management processes to improve repeatability and compliance across classified systems.


• Support troubleshooting and resolution of complex security and infrastructure issues involving a variety of information systems.


• Support the preparation for and execution of government security assessments, authorization reviews, inspections, and audits, including collection and presentation of objective evidence demonstrating control implementation.


• Provide technical cybersecurity guidance and mentoring to system administrators, ISSOs, and other program personnel.

Basic Qualifications

• Must be a U.S. Citizen.


• Bachelor's Degree with 8-12 years of experience, Master’s degree with 6-10 years of experience, or equivalent relevant experience and/or industry-standard certifications may be considered in lieu of degree.


• Must hold a current Active Top Secret security clearance to be considered along with sustained ability to be cleared to Special Access Programs and ability to obtain Top Secret/SCI security clearance.


• Must have a DoD 8140/8570 IAT level II or higher certification such as CompTIA Security+.


• Professional-level knowledge and hands‑on experience administering, engineering, or securing Windows and Linux operating systems, including enterprise server and workstation environments.


• Expert-level knowledge of virtualization technologies, enterprise storage platforms, and backup/recovery solutions, including the security considerations associated with each.


• Working knowledge of enterprise networking concepts and technologies, including TCP/IP, routing, switching, VLANs, firewalls, network segmentation, DNS, authentication, and secure network architecture.


• 3+ years of demonstrated experience supporting Special Access Program (SAP) environments and applying applicable cybersecurity requirements, including the RMF and JSIG.


• Experience interpreting cybersecurity requirements and translating security controls into technical configurations, engineering requirements, and system implementations.


• Experience implementing, assessing, and maintaining technical security controls across operating systems, networks, virtualization platforms, storage, and supporting infrastructure.


• Hands‑on experience implementing and maintaining DISA STIGs, SRGs, Nessus, and secure configuration baselines.


• Knowledge of enterprise security technologies and concepts, including Active Directory, Group Policy, endpoint security, centralized logging, auditing, privileged access, encryption, and access control.


• Experience supporting the system development and security lifecycle, including design, integration, testing, deployment, authorization, continuous monitoring, maintenance, and decommissioning.


• Ability to troubleshoot complex technical and cybersecurity issues spanning operating systems, networking, or other information system components.


• Strong technical documentation and communication skills with the ability to clearly communicate security risks, technical requirements, remediation strategies, and engineering recommendations to both technical and nontechnical stakeholders.


• Experience with the Risk Management Framework (RMF) and maintaining compliance artifacts such as SCAP scans, STIGs, and Nessus Vulnerability reports.


• Experience developing or maintaining technical procedures, system build documentation, configuration baselines, work instructions, scripts, or automation used to support secure and repeatable system deployments.


• Experience designing or securing air‑gapped environments including offline patching, software repositories, vulnerability management, and configuration management.

Preferred Qualifications

• ISC(2) Certification Information System Security Professional (CISSP) or Information System Security Engineering Professional (CISSP-ISSEP) certification.


• RedHat Certified System Administrator (RHCSA) certification.


• Demonstrated ability to independently interpret JSIG/RMF controls and translate them into practical technical architectures, configurations implementation guidance, and validation procedures.


• Experience developing and maintaining SIEM/log-management platforms such as Splunk, and endpoint security technologies to include DLP.

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: October 8, 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 $107,900.00 - $195,050.00 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.

Leidos Leidos is an industry and technology leader serving government and commercial customers with smarter, more efficient digital and mission innovations. Headquartered in Reston, Virginia, with 47,000 global employees, Leidos reported annual revenues of approximately $17.2 billion for the fiscal year ended January 2, 2026. For more information, visit www.Leidos.com.

Pay and Benefits

Pay and benefits are fundamental to any career decision. That's why we craft compensation packages that reflect the importance of the work we do for our customers.

Employment benefits include competitive compensation, Health and Wellness programs, Income Protection, Paid Leave and Retire.

• competitive compensation


• Health and Wellness programs


• Income Protection


• Paid Leave and Retire

Commitment and Diversity All qualified applicants will receive consideration for employment without regard to sex, race, ethnicity, age, national origin, citizenship, religion, physical or mental disability, medical condition, genetic information, pregnancy, family structure, marital status, ancestry, domestic partner status, sexual orientation, gender identity or expression, veteran or military status, or any other basis prohibited by law. Leidos will also consider for employment qualified applicants with criminal histories consistent with relevant laws.