Information System Security Engineer (ISSE) – Senior

Network Designs Inc.•McLean, VA

1d•Onsite

About The Position

NDi is seeking an experienced Information System Security Engineer (ISSE) - Senior to provide senior-level security engineering support for enterprise information systems within a large federal IT services program. The ISSE (Senior) serves as a technical authority responsible for supporting system owners and engineering teams in the design, implementation, and validation of security controls across complex information systems. This role supports Authorization to Operate (ATO) and ongoing authorization activities by applying FISMA, the NIST Risk Management Framework (RMF), and federal cybersecurity standards to ensure systems are secure, compliant, and operationally effective throughout their lifecycle.

Requirements

U.S. Citizenship is required
Must possess an active Top Secret (TS) clearance at the time of application
This position requires working onsite at one of the following locations, 5 days per week: Downtown Washington, DC; Huntsville, AL; or Clarksburg, WV
Bachelor's degree in Computer Science, Information Systems, Cybersecurity, Engineering, or a related technical discipline; or equivalent combination of education, training, and work experience.
Eight (8) or more years of progressive experience supporting federal information systems security engineering ; in absence of years of experience, certifications or past work may be used to show the level of experience needed to perform at this level.
Demonstrated experience supporting information systems through the full RMF lifecycle, including initial authorization and continuous monitoring.
Hands-on experience designing and implementing security controls aligned to NIST SP 800-53.
Experience supporting systems categorized under FIPS 199 (Moderate and High), including National Security Systems (NSS), as applicable.
Proven experience collaborating with system owners, architects, developers, and ISSOs to remediate technical security gaps and close POA&Ms.
Experience supporting system security architecture, boundary definition, and technical control inheritance.
Experience developing and maintaining RMF artifacts and supporting evidence within a Governance, Risk, and Compliance (GRC) tool environment.
Strong expertise in information system security engineering and secure system design.
In-depth knowledge of RMF and federal cybersecurity compliance requirements.
Experience implementing and validating controls related to identity and access management, logging, vulnerability management, and configuration baselines.
Ability to translate security requirements into actionable technical designs and implementation guidance.
Strong documentation, analytical, and communication skills.
Ability to operate effectively across large, multi-system enterprise environments.
Ability to mentor mid- and junior-level security engineers

Nice To Haves

CISSP (Associate or Full)
CISM
GSLC
Other senior-level cybersecurity or security engineering certifications aligned to RMF

Responsibilities

Provide senior-level security engineering support for enterprise information systems.
Design, implement, and validate technical security controls to support ATO and ongoing authorization.
Support development and review of system security architectures, boundaries, and control implementations.
Advise system owners and technical teams on secure system design and remediation strategies.
Lead or support preparation and maintenance of RMF artifacts, including system security plans and control implementation descriptions.
Support POA&M remediation and security impact analysis for system changes.
Support continuous monitoring activities and recurring security reviews.
Coordinate with assessment teams to resolve technical and documentation rework efficiently.
Serve as a senior technical advisor on information system security risk and compliance.
Collaborate with ISSOs, system engineers, and operations teams to ensure consistent and high-quality security implementation.
Mentor junior engineering staff and support knowledge sharing.
Contribute to process improvement initiatives focused on improving ATO quality, timeliness, and audit readiness