Senior Cybersecurity Engineer / Information System Security Engineer (ISSE)

Great Waters Federal i s part of the Seneca Nation Group (SNG) portfolio of companies . SNG is Seneca Holdings' federal government contracting business that meets mission-critical needs of federal civilian, defense, and intelligence community customers. Our portfolio comprises multiple subsidiaries that participate in the Small Business Administration 8(a) program. To learn more about SNG, visit the website and follow us on LinkedIn .

Our team of talented individuals is what makes us successful. To support our team, we provide a balanced mix of benefits and programs. Your total rewards package includes competitive pay, benefits, and perks, flexible work-life balance, professional development opportunities, and performance and recognition programs. We offer a comprehensive benefits package that includes medical, dental, vision, life, and disability, voluntary benefit programs (critical illness, hospital, and accident), health savings and flexible spending accounts, and retirement 401K plan. One of our fundamental principles is to offer competitive health and welfare benefits to our team members, providing coverage and care for you and your family. Full-time employees working at least 30 hours a week on a regular basis are eligible to participate in our benefits and paid leave programs. We pride ourselves on our collaborative work environment and culture, which embraces our mission of providing financial and non-financial benefits back to the members of the Seneca Nation.

Great Waters Federal is seeking a highly skilled and experienced Senior Cybersecurity Engineer / Information System Security Engineer (ISSE) to support cybersecurity engineering, security operations, vulnerability management, and continuous monitoring activities within Departent of Defense (DoD) information systems. The ideal candidate will possess a minimum of 10 years of relevant experience and demonstrate extensive hands-on technical expertise in vulnerability assessment and remediation, security configuration management, system hardening, endpoint protection, and enterprise systems administration.

This position requires a cybersecurity professional capable of independently identifying, assessing, mitigating, and remediating security vulnerabilities while maintaining compliance with applicable DoD cybersecurity requirements, National Institute of Standards and Technology (NIST) security standards, and organizational security policies. The Senior Cybersecurity Engineer will collaborate with Information System Security Managers (ISSMs), Information System Security Officers (ISSOs), system administrators, network engineers, and other technical stakeholders to maintain the security and operational readiness of mission-critical information systems.

Roles and Responsibilities include, but are not limited to :

Cybersecurity Engineering and Risk Management Framework (RMF)

Implement and maintain technical security controls in accordance with the NIST Risk Management Framework (RMF) and NIST Special Publication 800-53.

Support Information Security Continuous Monitoring (ISCM) activities in accordance with NIST SP 800-137.

Provide technical engineering support throughout the RMF authorization lifecycle. Assess the effectiveness of implemented security controls and identify technical compliance deficiencies.

Develop and implement corrective actions to address security control weaknesses.

Support the development and maintenance of System Security Plans (SSPs), security control implementation statements, assessment evidence, and Plans of Action and Milestones (POA&Ms).

Evaluate proposed system changes to determine cybersecurity impacts and maintain approved security configuration baselines. Provide technical evidence and remediation support for Authority to Operate (ATO) activities.

Collaborate with ISSOs and ISSMs to ensure continuous compliance with applicable security requirements.

Vulnerability Assessment, Management, and Remediation

• •Install, configure, administer, maintain, and troubleshoot Tenable Nessus vulnerability scanners. Administer and manage Tenable Security Center (Tenable.sc), including scanner integration, scan repositories, policies, credentials, and reporting.
• Conduct authenticated and unauthenticated vulnerability assessments across enterprise information systems.

Configure and manage automated vulnerability scanning schedules and assessment policies. Analyze vulnerability findings, assess associated risks, and prioritize remediation efforts based on severity, exploitability, and operational impact.

Develop and implement vulnerability mitigation and remediation strategies.

Coordinate with system administrators, engineers, and system owners to resolve identified security weaknesses.

Perform follow-up vulnerability scans to validate remediation effectiveness. Maintain vulnerability tracking records and produce technical reports documenting findings, remediation status, and residual risk. Support vulnerability management activities across Windows Server, Red Hat Enterprise Linux, and AWS environments.

DISA STIG Compliance and System Hardening

Implement and enforce applicable Defense Information Systems Agency (DISA) Security Technical Implementation Guides (STIGs) and Security Requirements Guides (SRGs).

Conduct automated and manual security compliance assessments using eSTIG tools, Security Content Automation Protocol (SCAP) scanning utilities, and approved assessment tools.

Analyze STIG findings and implement appropriate technical remediation measures.

• •Develop, implement, and maintain secure configuration baselines for supported operating systems and enterprise applications. Identify and investigate configuration deviations and implement corrective actions.
• Document compliance findings, remediation activities, and approved security deviations.

Validate system hardening and remediation effectiveness through automated scanning and manual verification.

Support cybersecurity inspections, audits, and continuous monitoring requirements. Ensure systems maintain compliance with applicable DoD security configuration standards.

Endpoint Security and HBSS Administration

Administer, configure, maintain, and troubleshoot Host-Based Security System (HBSS) infrastructure and applicable successor endpoint security technologies.

Manage endpoint security policies, agent deployments, software updates, and system health monitoring.

Administer endpoint security management platforms, including Trellix/McAfee ePolicy Orchestrator (ePO), as applicable.

Investigate endpoint security alerts and coordinate appropriate corrective actions.

Ensure endpoint protection configurations comply with applicable DoD security requirements.

Support endpoint security infrastructure upgrades, configuration changes, and operational troubleshooting.

Monitor endpoint protection effectiveness and resolve agent communication, policy enforcement, and system compliance issues.

Systems Administration and Configuration Management

• •Administer, configure, secure, and troubleshoot Red Hat Enterprise Linux (RHEL) and Microsoft Windows Server operating systems. Perform operating system installation, configuration, patch management, security hardening, and maintenance.
• Implement and maintain approved system configuration baselines.

Conduct security impact assessments for proposed system and infrastructure changes.

Support enterprise configuration management and change control processes.

Identify and resolve operating system vulnerabilities, misconfigurations, and security weaknesses.

Maintain technical documentation, system configuration records, and standard operating procedures.

Collaborate with infrastructure engineering teams to ensure secure deployment and reliable operation of enterprise systems.

Ensure system configurations remain compliant with organizational security policies and applicable DoD requirements.

AWS Cl