Information System Security Officer; ISSO

Information System Security Officer (ISSO)
The Opportunity

This role works directly with Department of Defense stakeholders, cybersecurity engineers, system administrators, software developers, enterprise architects, and program leadership to maintain the cybersecurity posture of assigned information systems. It is an opportunity to apply Risk Management Framework expertise to support mission-critical systems while ensuring compliance with Department of Defense cybersecurity requirements and continuous authorization objectives.

Work is primarily performed on-site at Scott Air Force Base, Illinois, supporting government and contractor teams in mission-focused environments.

C5T Corporation is a Service-Disabled Veteran-Owned Small Business headquartered at Scott Air Force Base, Illinois. Founded in 2005 by three veterans, C5T values practical, innovative-minded professionals with a passion for mission success. We specialize in bridging the gap between operational and technical domains to support critical Department of Defense missions.

Core Values:
Integrity, Excellence, Patriotism

C5T is seeking an Information System Security Officer (ISSO) to support Department of Defense information systems by managing cybersecurity authorization activities, maintaining Risk Management Framework compliance, and supporting continuous monitoring. This position serves as a key member of the cybersecurity team responsible for maintaining Authorization to Operate packages, developing security documentation, coordinating assessments, and ensuring compliance with Department of Defense cybersecurity policies and National Institute of Standards and Technology guidance.

Location:

Scott Air Force Base, Illinois. Work will primarily take place in government work spaces with limited telework based on mission requirements.

• Develop, maintain, and update System Security Plans (SSPs) for assigned systems.
• Manage Plans of Action and Milestones (POA&Ms) from identification through remediation and closure.
• Compile, maintain, and submit Authorization to Operate (ATO) packages.
• Conduct continuous monitoring activities in accordance with the Risk Management Framework (RMF).
• Utilize Enterprise Mission Assurance Support Service (eMASS) for Governance, Risk, and Compliance workflow management.
• Coordinate with Information System Security Engineers (ISSEs), Security Operations personnel, and system owners to validate security controls.
• Develop Security Assessment Plans (SAPs) and support Security Assessment Report (SAR) activities.
• Draft supply chain risk management documentation.
• Support cybersecurity architecture and RMF planning activities.
• Participate in security reviews, audits, and inspections.
• Develop and maintain cybersecurity documentation and system artifacts.
• Support vulnerability remediation and compliance reporting.
• Ensure assigned systems comply with Department of Defense cybersecurity policies and National Institute of Standards and Technology Special Publication 800-53 Revision 5.

• Active Secret or Top Secret security clearance.
• Three to five years of Risk Management Framework and Authorization to Operate experience within Department of Defense or federal environments.
• Hands‑on experience with Enterprise Mission Assurance Support Service (eMASS).
• Working knowledge of National Institute of Standards and Technology Special Publication 800-53 Revision 5 and Department of Defense Risk Management Framework processes.
• Demonstrated ability to independently author System Security Plans and manage Plans of Action and Milestones.
• Strong written, verbal, analytical, and problem‑solving skills.
• Bachelor's degree in Computer Science, Cybersecurity, Information Technology, Information Systems, Software Engineering, Data Science, or equivalent experience.

• Experience with Enterprise Mission Assurance Support Service Reporter (eMASSer) or similar automation tools.
• Exposure to cloud‑hosted or hybrid authorization boundaries.
• Familiarity with the Department of Defense Risk Management Framework Knowledge Service.
• Certified Ethical Hacker (CEH) or equivalent Department of Defense 8140 certification.
• Experience supporting mission‑critical Department of Defense systems.

• Competitive salary
• Medical, dental, and vision insurance options
• 401(k) with company match
• Flexible Spending Account (FSA)
• Supplemental benefits including accident, critical illness, and hospital indemnity coverage
• Company‑paid life insurance
• Employee Assistance Program
• 10 paid holidays annually
• Responsible Paid Time Off aligned with mission needs

C5T is a merit‑based employer committed to affirmative action and nondiscrimination for all qualified applicants, including individuals with disabilities and protected veterans, in accordance with Section 503 and the Vietnam Era Veterans' Readjustment Assistance Act (VEVRAA).