Information System Security Engineer with Security Clearance

Job Description Tharros is seeking an experience Information System Security Engineer to support cybersecurity, Risk Management Framework (RMF), and Authority to Operate (ATO) activities for DoD/federal information systems. The ISSE will work closely with ISSOs, ISSMs, system owners, security teams, engineers, and government stakeholders to prepare, manage, and submit security documentation and support systems throughout the RMF/ATO lifecycle. The ideal candidate is a hands-on cybersecurity professional who can take ownership of RMF and ATO activities, develop and maintain a complete authorization package, work effectively in eMASS, coordinate with ISSOs/ISSMs and engineering teams, and drive security findings toward resolution.

• Support the implementation and execution of the NIST Risk Management Framework (RMF).
• Develop, review, and maintain RMF security documentation and artifacts.
• Prepare, coordinate, and support Authority to Operate (ATO) packages and submissions.
• Work within eMASS to create, update, and maintain system security artifacts.
• Support security control implementation, assessment, validation, and remediation activities.
• Develop and maintain System Security Plans (SSPs), Security Assessment Reports (SARs), Plans of Action and Milestones (POA&Ms), and supporting documentation.
• Collect and maintain security control implementation evidence.
• Coordinate with ISSOs, ISSMs, system owners, security control assessors, engineers, and government stakeholders.
• Track security findings, vulnerabilities, and POA&M items through resolution.
• Support DISA STIG/SRG compliance and vulnerability remediation activities.
• Participate in RMF reviews, security assessments, authorization activities, and ATO decision processes.
• Ensure security documentation and system security artifacts remain accurate, current, and audit-ready.
• Provide cybersecurity and RMF guidance to engineering and project teams. Requirements
• Active TS/SCI security clearance required.
• DoD IAT Level II certification required, such as Security+ or another DoD-approved IAT Level II baseline certification.
• Demonstrated experience as an ISSE, Security Engineer, ISSO, or similar cybersecurity professional.
• Hands-on experience with the NIST RMF and ATO lifecycle.
• Experience preparing and supporting ATO submissions.
• Hands-on experience with eMASS.
• Working knowledge of NIST SP 800-53 security controls.
• Experience developing and maintaining SSPs, SARs, POA&Ms, security control evidence, and other RMF artifacts.
• Experience with DISA STIGs/SRGs and vulnerability management.

Summary Tharros combines extensive cyber defense knowledge with the world's preeminent vulnerability expertise to identify and defend against attacks before they become problems. Working at mission speed, we harden mission systems faster and secure them for longer, so agencies never lose the mission edge. Tharros lifts the veil of enterprise cybersecurity to detect zero days before they affect you, enabling mission maneuverability and the confidence to move missions forward.

In the ever-evolving realm of cyberspace, we are dedicated to becoming the paramount defender in the 5th warfighting domain. By pioneering innovative security solutions and fostering an environment of continuous learning and vigilance, we aim to protect the interests of our nation's security. Our commitment to excellence in cybersecurity will establish new benchmarks, transforming the digital landscape into a secure and thriving frontier for future generations. Tharros. See Everything. Secure Anything. Tharros is committed to hiring and retaining a diverse workforce.

We are proud to be an Equal Opportunity/Affirmative Action Employer and make employment decisions without regard to race, color, religion, creed, sex, sexual orientation, gender identity, marital status, national origin, age, veteran status, disability, or any other protected status.