Information Systems Security Engineer (ISSE) SME

Leidos has a new and exciting opportunity for an Information Systems Security Engineer (ISSE) SME in our Intel Sector's (IS) Analysis Solutions Business Area (ASBA). Our talented team is at the forefront in Security Engineering, Computer Network Operations (CNO), Mission Software, Analytical Methods and Modeling, Signals Intelligence (SIGINT), and Cryptographic Key Management.

At Leidos, we offer competitive benefits, including Paid Time Off, 11 paid Holidays, 401K with a 6% company match and immediate vesting, Flexible Schedules, Discounted Stock Purchase Plans, Technical Upskilling, Education and Training Support, Parental Paid Leave, and much more. Join us and make a difference in National Security!

Job Description The Information Systems Security Engineer (ISSE) SME is responsible for designing, developing, and implementing secure information systems that support mission operations. The ISSE collaborates with multidisciplinary teams - including Information Systems Security Managers (ISSMs), software developers, systems engineers, and government stakeholders—to integrate effective security controls and ensure systems remain resilient against evolving threats and vulnerabilities. The ISSE also installs and maintains security scanning tools, performs vulnerability assessments, and reviews scan results to identify and remediate security risks. Additionally, the role ensures security tools and controls are properly integrated into the DevSecOps CI/CD pipeline, supporting continuous security testing and monitoring throughout the system lifecycle.

Primary Responsibilities:

• Applying system security engineering principles in areas such as system security design, lifecycle engineering, authentication and authorization mechanisms, cryptography, intrusion detection, contingency planning, incident handling, auditing, configuration management, and change control.
• Conducting or supporting technical cybersecurity assessments and security audits.
• Coordinating with cybersecurity personnel and recommending mitigation strategies to reduce risk.
• Identifying system vulnerabilities and instances of non-compliance with cybersecurity standards and regulatory requirements.
• Performing vulnerability scans using approved customer tools and generating reports detailing findings and remediation progress.
• Collaborating with DevSecOps teams to review vulnerability scan results and support remediation of identified security findings.
• Install, configure, and maintain security scanning and monitoring tools, ensuring they are properly integrated within system environments and DevSecOps pipelines.
• Support the Risk Management Framework (RMF) authorization process by reviewing security documentation and providing risk-based recommendations to stakeholders regarding system risk posture as part of Authority to Operate (ATO) activities while managing and tracking Plans of Action and Milestones (POA&Ms) for customer-sponsored systems, coordinating with key stakeholders including ISSOs, ISSEs, ISSMs, and Security Control Assessors (SCAs).

Basic Qualifications:

• MS degree and 15 or more years of prior relevant experience.
• Additional years of experience may be substituted in lieu of a degree.
• Must have an active TS/SCI with a Polygraph, to be considered.
• Experience conducting routine vulnerability scanning, providing formal and informal reports to technical teams, and tracking remediation activities.
• Experience reviewing security bulletins, threat intelligence, and vulnerability advisories to stay informed of current threats and emerging attack techniques.
• Experience monitoring system and network security using Security Information and Event Management (SIEM) tools.
• Investigate and respond to cyber security incidents (system and/or network breaches, malware attacks).
• Experience tracking Common Vulnerabilities and Exposures (CVEs) and mapping them to internal controls and remediation strategies.
• Experience auditing systems to ensure compliance with secure configuration baselines and cybersecurity policies
• Experience using at least two vulnerability scanning tools, such as AWS Inspector, Tenable Security Center, Rapid7 Nexpose, SonarQube, Fortify, or OWASP security tools.
• At least 1 Certification: CISSP, Splunk, Network+, Security+, OSCP, CEH, CASP+, ISSEP

Preferred Qualifications:

• Experience with Dynamic Application Security Testing (DAST) and Static Application Security Testing (SAST) tools.
• Experience using Splunk, including creating dashboards and security monitoring visualizations.
• Familiarity with cloud computing platforms, such as AWS, Oracle Cloud, or Google Cloud Platform (GCP).

Pay Range: Pay Range $154,050.00 - $278,475.00 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

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 Retirement. More details are available here.

Securing Your Data Leidos will never ask you to provide payment-related information at any part of the employment application process. And Leidos will communicate with you only through emails that are sent from a Leidos.com email address. If you receive an email purporting to be from Leidos that asks for payment-related information or any other personal information, please report the email to View email address on click.appcast.io.

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.