Senior Information Systems Security Engineer (ISSE) – TS/SCI

Dark Horse Tech; Mississippi; On-site; USD 140,000 - 200,000; Full time

Job summary

Dark Horse Technologies is seeking a Senior Information Systems Security Engineer (ISSE) to support RMF accreditation activities within the IC. This on-site role at CNMOC Headquarters requires active TS/SCI clearance and will focus on transitioning CDS RMF packages into Xacta for ongoing government management.

The candidate will develop RMF artifacts, ensure compliance with IC overlays and NIST SP 800-53 Rev.

Qualifications

• Minimum of five years direct, hands-on RMF package processing experience for IC agencies.
• Demonstrated RMF package development/management within IC environments.
• Strong understanding of JWICS security requirements and operating environments.
• Knowledge of Intelligence Community security overlays and RMF requirements.
• Thorough knowledge of NIST SP 800-53 Rev. 4/5 controls.
• Experience with system authorization, accreditation, assessment, POA&M, and continuous monitoring.

Responsibilities

• Lead and support the transition of CDS RMF packages into Xacta 360.
• Develop, update, review, and maintain RMF authorization documentation in Xacta.
• Evaluate security packages and determine updates to meet IC RMF requirements.
• Apply Intelligence Community overlays, controls, and assessment requirements.
• Support RMF activities across authorization lifecycle including monitoring.
• Review controls against NIST SP 800-53 Rev.4/5 requirements.
• Coordinate with owners, cybersecurity staff, ISSMs, ISSOs, assessors, and government stakeholders.
• Ensure packages are ready for transition to Government personnel for lifecycle management.

Skills

RMF experience

Xacta

IC environments

NIST SP 800-53

Technical writing

Independently drive RMF

Tools

Xacta 360

Xacta IA Manager

Job description

Location:On-site – CNMOC Headquarters
Clearance: Active TS/SCI required
Anticipated Start: September 2026, contingent upon task order award
Employment Type: Full-time

Position Overview

Dark Horse Technologies is seeking a Senior Information Systems Security Engineer (ISSE) with extensive experience supporting Risk Management Framework (RMF) accreditation activities within the Intelligence Community (IC).

This position will support a focused, approximately one-year effort to transition existing operational Cross Domain Solution (CDS) RMF authorization packages into Xactafor ongoing management by the Government. The successful candidate must bring direct, hands‑on experience using Xacta 360 or legacy Xacta IA Managerto develop, process, maintain, and support RMF authorization packages for IC environments.

This is an on‑site position at CNMOC Headquartersand requires an active TS/SCI clearance.

Key Responsibilities

• Lead and support the transition of existing operational CDS RMF packages into Xacta 360.
• Develop, update, review, and maintain RMF authorization documentation within Xacta.
• Evaluate existing security authorization packages and determine required updates or remediation to align with IC RMF requirements.
• Apply applicable Intelligence Community overlays, security controls, and assessment requirements.
• Support RMF activities throughout the authorization lifecycle, including control implementation, assessment, remediation, authorization, and continuous monitoring.
• Review and validate security control implementation against NIST SP 800-53 Rev. 4 and Rev. 5 requirements.
• Develop and maintain artifacts including Security Plans, control implementation statements, assessment evidence, POA&Ms, risk documentation, and supporting authorization materials.
• Coordinate with system owners, cybersecurity personnel, engineers, ISSMs, ISSOs, security control assessors, and Government stakeholders to resolve RMF deficiencies.
• Support RMF accreditation and authorization activities for systems operating within JWICS and Intelligence Community environments.
• Identify gaps between existing Navy RMF documentation and IC/Xacta requirements and develop an efficient transition approach.
• Ensure authorization packages are organized and documented so they can be effectively transitioned to Government personnel for continued lifecycle management.
• Provide knowledge transfer and technical guidance to Government cybersecurity personnel responsible for sustaining the packages following completion of the transition effort.

Required Qualifications

• Minimum of five (5) years of direct, hands‑on experience using Xacta 360 or legacy Xacta IA Manager to process RMF packages for Intelligence Community agencies.
• Demonstrated experience developing and managing RMF authorization packages within IC environments.
• Strong understanding of JWICS security requirements and operating environments.
• Demonstrated knowledge of applicable Intelligence Community security overlays and RMF requirements.
• Thorough knowledge of NIST SP 800-53 Rev. 4 and/or Rev. 5 security controls.
• Experience supporting system authorization, accreditation, assessment, POA&M management, and continuous monitoring activities.
• Ability to interpret cybersecurity requirements and translate them into appropriate RMF documentation and implementation guidance.
• Strong written and verbal communication skills with the ability to work directly with technical and Government stakeholders.
• Ability to work independently and drive RMF packages through completion within established timelines.

Clearance Requirement

• Active Top Secret clearance with SCI eligibility/access required.

Preferred Qualifications

• Experience supporting Cross Domain Solutions (CDS) or other highly controlled classified systems.
• Experience transitioning RMF packages between different governance, risk, and compliance platforms.
• Familiarity with Navy cybersecurity environments and the differences between eMASS-based Navy RMF processes and Xacta-based IC processes.
• Experience supporting operational DoD or IC systems through authorization and continuous monitoring.
• Relevant cybersecurity certifications such as CISSP, CAP/CGRC, CASP+/SecurityX, or equivalent.

Ideal Candidate

The ideal candidate is not simply an RMF practitioner. We are specifically seeking an experienced Xacta practitioner who has personally developed and processed authorization packages for Intelligence Community customers and can immediately begin working within an IC RMF environment.

This role is particularly well suited for an experienced ISSE, ISSM, cybersecurity engineer, or RMF specialist who understands both the technical and documentation requirements associated with moving operational systems through the IC authorization process.

Additional Information

Employment is contingent upon task order award and verification of required security clearance.

Dark Horse Technologies LLC is an Equal Opportunity Employer.