Strategic ISSO (TS) — RMF/ATO Expert

The Mission Essential Group, LLC; Fairfax (VA); On-site; USD 120,000 - 135,000; Full time

Benefits offered by this job

Medical insurance

Dental insurance

Vision insurance

Life insurance

Disability insurance

Paid time off

Retirement benefits

Job summary

The Mission Essential Group, LLC (MEG) is a Fairfax, Virginia-based provider of information management and cybersecurity services, delivering RMF/A&A support, vulnerability management, and continuous monitoring across DoD programs. This ISSO role focuses on implementing security controls, assessing authorization, and coordinating with stakeholders to maintain secure, compliant information systems.

This position requires an active TS clearance and a strong background in RMF, eMASS/Xacta, and

Qualifications

• Active TS clearance.
• Bachelor's degree in computer science, Information Systems, Cybersecurity, Information Technology.
• Minimum of five (5) years of Cyber Security experience.
• Minimum of three (3) years of RMF experience per NIST SP 800-37 Rev. 2.
• Working knowledge of federal and DoD cybersecurity standards (NIST SP 800-60, SP 800-53 Rev 5, CNSSI 1253 Rev 5, DoDI 8510.01).
• Experience supporting SIPRNet-connected systems and environments.
• Strong knowledge of Windows server and workstation administration.
• Experience managing RMF packages using eMASS/Xacta.
• Experience with encryption, data protection, IAM, PAM, vulnerability management, and continuous monitoring.
• Current CompTIA Security+ or equivalent 8570/8140 baseline.

Responsibilities

• Support A&A activities including RMF package development, security control implementation, assessment, validation, monitoring, POA&M tracking, and ATO processes using eMASS and/or Xacta.
• Verify changes to systems that may impact security posture and authorization status.
• Serve as liaison between system owners, ISSMs, engineers, assessors, and cybersecurity stakeholders.
• Ensure day-to-day implementation, oversight, monitoring, and security compliance of multiple information systems.
• Lead meetings with SMEs to identify, document, validate, and track cybersecurity requirements.
• Conduct vulnerability assessments and security scans with Nessus and related tools.
• Implement and track protective and corrective actions for incidents, vulnerabilities, or deficiencies.
• Perform risk assessments and assist with mitigation of cybersecurity risks.
• Support installation, configuration, and maintenance of hardware/software in secure environments.
• Apply security patches and configuration changes to maintain compliance.
• Develop Security Control Traceability Matrices (SCTMs) mapping requirements to DoD/NIST controls.
• Stay current with federal/DoD cybersecurity policies and framework updates.
• Support audits, compliance reviews, and security inspections.

Skills

RMF experience

Vulnerability management

Security scanning

Education

Bachelor's degree in computer science/Information Systems/Cybersecurity/IT

Tools

eMASS

Xacta

Nessus

SCAP Compliance Checker

Job description

The Mission Essential Group, LLC (MEG) is a Fairfax, Virginia-based provider of information management and cybersecurity services, delivering RMF/A&A support, vulnerability management, and continuous monitoring across DoD programs. This ISSO role focuses on implementing security controls, assessing authorization, and coordinating with stakeholders to maintain secure, compliant information systems.

This position requires an active TS clearance and a strong background in RMF, eMASS/Xacta, and