Information Systems Security Engineer

Leidos LLC; Maryland; On-site; USD 108,000 - 195,000; Full time

Job summary

Leidos is seeking an Information Systems Security Engineer to support our DoD customer onsite. The ISSE shall perform security assessments, identify vulnerabilities, and guide mitigation across complex computing environments to align with IA standards.

Required: Active TS/SCI with Poly, 7+ years as ISSE/Network Engineer, BS in a related field, CASP+ or CISSP, and strong writing and briefing abilities for senior DoD officials.

Qualifications

• Bachelor’s degree in a relevant field with 7+ years of ISSE or Network Engineer experience.
• Certifications: CASP+ or CISSP (required).
• Must have TS/SCI with Polygraph clearance.
• Strong written and briefing skills for senior DoD officials.
• Knowledge of NIST SP 800 series, CNSSI 1253 and DoD 8500."

Responsibilities

• Perform or review technical security assessments across computing environments.
• Identify vulnerabilities and ensure compliance with IA standards and regulations.
• Develop and integrate information security functionalities within architectures.
• Support security planning, risk analysis, certification, and awareness activities.
• Review C&A documentation for completeness and compliance.

Skills

Security assessments

Strong writing skills

Briefing to DoD officials

Education

Bachelors in CS/InfoSec/related field

Job description

Leidos is currently seeking an Information Systems Security Engineer to support our customer onsite. The ISSE shall perform, or review, technical security assessments of computing environments to identify points of vulnerability, non-compliance with established IA standards and regulations and recommended mitigation strategies. This includes: Validates and verifies system security requirements definitions and analysis and establishes system security design Designs, develops, implements and/or integrates IA and security systems and system components including those for networking, computing and enclave environment to include those with multiple enclaves and with differing data protection/classification requirements Builds IA into systems deployed to operation environments Assist architects and systems developers in the identification and implementation of appropriate information security functionality to ensure uniform application of Agency security policy and enterprise solutions Supports the building of security architectures Enforces the design and implementation of trusted relations among external systems and architecture Assesses and mitigates system security threats/risk throughout the program life cycle Contributes to the security planning, assessment, risk analysis, risk management, certification and awareness activities for system and networking operations Reviews C&A documentation, providing feedback on completeness and compliance of its content

CLEARANCE REQUIRED:

Active TS/SCI with Polygraph.

Minimum requirements include: Bachelor’s degree from an accredited university ideally in Computer Science, Information Assurance, Information Security System Engineering or related field with a minimum of 7+ years of experience as an Information Systems Security Engineer (ISSE) or Network Engineer on programs and/or contracts with the customer space. 4 additional years of experience in lieu of Technical Degree will be accepted. CASP+ OR CISSP a firm requirement Strong writing skills Confidence and ability to present briefing to senior level DoD officials in both prepared briefings and/or in ad hoc discussions.

Additionally, the candidate must also possess the following knowledge, skills and abilities: Should have working knowledge of security/ or network components, i.e. routers, firewalls, IPS, IDS, etc Experience in identifying, researching, characterizing, and documenting security weaknesses related to operating systems, software applications, firmware, network hardware components, as well as network architecture design and documented policies and procedures. Experience developing and documenting system security requirements and conducting requirements gap analysis. Knowledge of, and practical experience with the NIST Special Publications 800 Series, CNSSI 1253, and DoD 8500. Experience with network technologies and the ability to demonstrate knowledge of network protocols, communications systems and architectures Should have significant hands on experience implementing security and/or network components, i.e. routers, firewalls, IPS, IDS, etc. Ability to work independently within a schedule and with little direction.

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: June 29, 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 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 [e-mail].

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.