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

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: Tasks shall include, but are not limited to, the following: * 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 (lA) 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 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