Information System Security Engineer (ISSE) (2026-0170)

Acclaim Technical Services, Inc.; Chantilly (VA); On-site; USD 120,000 - 160,000; Full time

Job summary

Acclaim Technical Services, Inc. in Chantilly, VA is seeking an Information System Security Engineer (ISSE) with TS/SCI clearance and polygraph to support data and systems integration and A&A activities. You will design security controls, perform vulnerability assessments, and liaise with ISSMs to resolve issues in a multi‑enclave environment.

A bachelor’s degree plus 8 years of experience is required. The role focuses on ensuring compliant documentation, embedding IA systems, and coordinating

Qualifications

• Prior ISSE and Network Engineering experience on technical communications or intelligence programs.
• Bachelor's degree plus eight years of experience required.
• TS/SCI clearance with polygraph is required.

Responsibilities

• Design and embed security controls into system architectures.
• Ensure vulnerability scans run routinely and patch issues with admins/developers.
• Review A&A documentation and ensure completeness and compliance.
• Understand computer architecture, networking, OS, and network security.
• Collaborate with ISSMs to resolve issues.
• Develop, implement, and integrate IA and security systems across environments.
• Review security assessments to identify vulnerabilities and non‑compliance.
• Create and review A&A Body of Evidence and feedback on content.
• Advise Sponsor customers on Lifecycle Assessment and Authorization.
• Maintain baselines and CM items, including security event monitoring policies.
• Coordinate changes through Sponsor's approval processes.
• Maintain documentation per agency regulations for each project.
• Enforce trusted interfaces among external systems and architectures.
• Use COTS/GOTS and custom tools to scan, contain, mitigate and remediate threats.
• Protect information systems from unauthorized access and disclosure.
• Recognize intrusion indicators through thorough reviews of events.

Skills

ISSE Experience

Network Engineering

Security Architecture

TS/SCI clearance

Polygraph

Education

Bachelor's Degree + 8 years

Job description

Acclaim Technical Services, founded in 2000, is a leading cyber operations, intelligence solutions and operations, network infrastructure, engineering and business enablement and enterprise operations company supporting a wide range of U.S. Federal agencies. We are an Employee Stock Ownership Plan (ESOP) company, which is uncommon within our business sector. We see this as a significant strength, and it shows: ATS is consistently ranked as a top workplace among DC area firms and continues to grow.

We are actively hiring an Information System Security Engineer (ISSE) with TS/SCI clearance and polygraph to join our Data and Systems Integration Division, working in Chantilly, VA to provide Support and administer cyber security projects and Assessment & Authorization (A&A) activities within the Sponsor’s organization.

ROLES AND RESPONSIBILITIES

• Technical cybersecurity role responsible for designing and embedding security controls into system architectures
• Ensure scans for all systems are run on a routine basis and work with system administrators/developers to patch vulnerabilities and policy failures
• A&A -review and complete required technical documentation (Accounts Management Plan, SOPs, etc.)
• Understanding of computer architecture, networking, operating systems, and network security
• Work with ISSMs to resolve any issues
• Develop, implement, and/or integrate Information Assurance (IA) and security systems, including those for networking, computing, virtualization, cloud, and enclave environments, to include those with multiple enclaves and with differing data protection/classification requirements.
• Review and conduct technical security assessments of computing environments to identify points of vulnerability, non‑compliance with established Information Assurance (IA) standards and regulations, and recommend mitigation strategies.
• Create and review Assessment and Authorization (A&A) Body of Evidence documentation and provide feedback on completeness and compliance of its content.
• Advise and assist the Sponsor's customers with the Lifecycle Assessment and Authorization process.
• Ensure all program activities maintain system baselines and configuration management items, including security event monitoring policies, in a manner determined and agreed to by the COTR and the Sponsor's management.
• Ensure changes are made using the Sponsor’s approved cybersecurity approval process and are coordinated and scheduled.
• Maintain appropriate levels of documentation deemed acceptable by Agency regulations and guidelines for each individual project, including operations and maintenance information, operations guides, design documents, scans, and overall concepts of operations.
• Enforce the design and implementation of trusted interfaces among external systems and architectures.
• Utilize COTS/GOTS and custom tools in order to scan, identify, contain, mitigate and remediate vulnerabilities and intrusions.
• Protect information and information systems from unauthorized access, use, disclosure, disruption, modification, perusal, inspection, recording and destruction.
• Recognize potential, successful, and unsuccessful intrusion attempts and compromises through thorough reviews and analyses of relevant event detail and summary information.

REQUIRED EDUCATION & EXPERIENCE

• Prior ISSE and Network Engineering experience working on a technical communication or intelligence collection program.
• Bachelors Degree + 8 years
• TS/SCI with polygraph

EQUAL EMPLOYMENT OPPORTUNITY (EEO) STATEMENT

ATS is committed to a program of equal employment opportunity without regard to race, color, ethnicity, national origin, ancestry, citizenship, sex, pregnancy, marital status, sexual orientation, age, religion/creed, hairstyles and hair textures, handicap/disability, genetic information/history, military/veteran status, or any other characteristic or condition protected by applicable law. We support the employment and advancement in employment of individuals with disabilities and of protected veterans, and we treat qualified individuals without discrimination on the basis of their physical or mental disability or veteran status.