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

Requirements

Active Top Secret clearance with contingency on DOD CAS granting SCI eligibility; 10+ years of related cybersecurity experience; At least 2 years of recent experience in A&A, FISMA compliance, IC cybersecurity policy and standards, continuous monitoring, CDS, and secure cloud and hybrid engineering; Experience applying NIST 800 series, CNSSI 1253, security controls, and RMF principles; Experience with emerging security risk management practices, including automation of A&A and continuous monitoring activities; CISM, CAP, or GRC certification, or comparable demonstrable experience; Experience developing, reviewing, or maintaining SSPs, POA&Ms, risk exceptions, contingency plans, privileged user documentation, ATO packages, and continuous monitoring evidence; Experience working with GRC tools and coordinating with technical teams to remediate vulnerabilities and maintain authorization readiness; Strong written and verbal communication skills; Ability to work onsite at a Government-approved location as required

Nice to have

Prior DHS, Intelligence Community, DoD, CISO office, ISSM, AO, SCA, or national security ISSO experience; Experience supporting large ISSO portfolios, classified systems, hybrid cloud environments, DevSecOps evidence collection, continuous monitoring, and audit readiness; Experience with Archer, eMASS, Xacta, ACAS, Tenable.sc, Splunk, GitLab, Axonius, STIG/SCAP validation, or related Federal cybersecurity tools; Experience with AWS, Microsoft Azure, Microsoft 365, or other cloud platforms; Experience supporting TS/SCI, SCIF, cross-domain, or secure mission environments

Benefits

Competitive compensation and comprehensive benefits including medical, dental, vision and disability coverage; Savings & retirement; Paid leave; Training & certification reimbursement of up to $5,250 per year; Team member referral bonuses; Tharros Leadership Development Program; Training opportunities, tools and resources