Information Systems Security Engineer

Location: Linthicum, MD

Time Type: Full time

Job Description

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

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.