Senior Information Systems Security Officer

Tharros is seeking a Senior Information Systems Security Officer to support a DHS Intelligence and Analysis cybersecurity program in the National Capital Region.

This role will support ISSO operations across a complex Federal cybersecurity environment, including Assessment and Authorization, continuous monitoring, ATO package maintenance, POA&M management, security artifact quality, cloud and hybrid system support, and cybersecurity compliance.

The ideal candidate is a hands-on ISSO who can maintain accurate authorization evidence, coordinate with technical teams, and help keep mission systems secure, compliant, and authorization-ready.

Responsibilities: Perform ISSO duties for assigned Federal information systems.Support RMF activities, including system categorization, control implementation support, assessment readiness, authorization package maintenance, and ongoing monitoring.Develop, review, validate, and maintain security artifacts such as SSPs, POA&Ms, risk exceptions, contingency plans, privileged user documentation, and privacy-related artifacts.Create, maintain, and monitor ATO packages in GRC tools.Support POA&M development, validation, remediation tracking, exception documentation, closure, and reporting.Collaborate with system owners, ISSOs, ISSMs, developers, engineers, assessors, and other stakeholders to address vulnerabilities, security findings, and remediation actions.Review vulnerability scan results and support recurring continuous monitoring activities.Support audit log review, alert response, and documentation of follow-up actions.Ensure assigned systems remain aligned with applicable cybersecurity policies, procedures, and decommissioning requirements.Support quarterly cybersecurity performance and compliance reporting.Provide ISSO support across hybrid environments, including classified and unclassified on-premise systems, cloud-based systems, DevSecOps environments, and agile development teams.Support security for operating systems and technologies including Linux, Windows, open-source operating systems, and cloud platforms.Support Cross Domain Solution security governance, assessment, and authorization activities.Help improve ISSO workflows, evidence management, POA&M tracking, continuous monitoring, and risk reporting through automation and repeatable processes.Translate compliance status, vulnerability data, and remediation progress into clear updates for technical and leadership stakeholders.