Senior Information Systems Security Officer (Sr. ISSO)

Celestar Corporation; Washington (District of Columbia); On-site; USD 125,000 - 200,000; Full time

Job summary

Celestar Corporation seeks a Senior Information Systems Security Officer (ISSO) to lead cybersecurity and RMF activities for critical systems. You will coordinate with engineers, operators, and government stakeholders to maintain Authority to Operate (ATO) and ensure ongoing compliance across the system lifecycle.

The role requires active TS/SCI with polygraph, Security+ or equivalent, and 18+ years in cybersecurity, with hands-on RMF, IATT/ATO experience, and proficiency in XACTA and Splunk.

Qualifications

• Active TS/SCI with polygraph
• Security+ or equivalent DoD IAT II/III
• 18+ years in cybersecurity or related field
• Experience as ISSO/ISSE or similar
• Experience coordinating RMF activities and ATO processes
• Proficiency with XACTA for RMF documentation
• Experience with RMF and IATT/ATO
• Strong communication with stakeholders
• Experience implementing NIST 800-53 controls

Responsibilities

• Lead cybersecurity and compliance for mission-critical systems
• Ensure security compliance and support authorization activities
• Coordinate with engineers, operations, and government stakeholders
• Develop and maintain SSPs, SAPs, POA&Ms, and artifacts
• Support security assessments and remediation efforts
• Implement Zero Trust across enterprise and cloud environments
• Manage risk findings, mitigation, and compliance tracking
• Utilize Splunk for security monitoring and reporting
• Coordinate with ISSMs, ISSEs, System Owners, and AOs

Skills

Active TS/SCI with Polygraph

Security+ / DoD IAT II/III

XACTA RMF

Splunk

ISSO / ISSE experience

Security controls (NIST 800-53)

Education

Bachelor's degree in Cybersecurity or related

Master's degree may substitute for 6 years

Tools

XACTA

Splunk

Job description

Senior Information Systems Security Officer (Sr. ISSO)

Summary

The Senior Information Systems Security Officer (ISSO) will lead cybersecurity and compliance efforts supporting mission-critical systems throughout the system lifecycle. The ISSO will ensure security compliance, support authorization activities, manage risk, and coordinate with engineering, operations, and government stakeholders to maintain Authority to Operate (ATO) for enterprise systems. The role includes implementation of RMF controls, development of security documentation, participation in assessments, and support of Zero Trust security architectures.

Key Responsibilities

• Conduct technical security assessments and evaluate system security posture.
• Ensure compliance with applicable security frameworks and regulatory requirements.
• Support certification, accreditation, IATT, and ATO activities.
• Collaborate with developers, system administrators, database administrators, and testers to ensure security is integrated throughout the development lifecycle.
• Support security assessment events and remediation efforts.
• Develop, maintain, and manage security documentation including SSPs, POA&Ms, SAPs, and assessment artifacts.
• Utilize XACTA to manage RMF documentation and authorization activities.
• Implement and validate NIST 800-53 security controls.
• Apply Zero Trust principles to cloud-native and enterprise environments.
• Manage risk assessments, findings, mitigation strategies, and compliance tracking.
• Coordinate with ISSMs, ISSEs, System Owners, Security Control Assessors (SCAs), and Authorizing Officials (AOs).
• Support security monitoring and compliance reporting activities utilizing Splunk and related cybersecurity tools.

Required Qualifications

• Active TS/SCI with Active Polygraph.
• Security+ or equivalent DoD IAT Level II/III certification.
• 18 years of experience in Cybersecurity, Information Assurance, Security Engineering, Systems Engineering, or related field.
• Experience serving as an ISSO, ISSE, or similar cybersecurity role.
• Proficiency with XACTA and the Risk Management Framework (RMF).
• Experience managing IATT and ATO processes.
• Proficiency with Splunk.
• Experience conducting architecture and security compliance assessments.
• Experience implementing and maintaining security documentation including:
  • System Security Plans (SSPs)
  • Security Assessment Plans (SAPs)
  • Plans of Action and Milestones (POA&Ms)
  • Security assessment artifacts
• Experience implementing security controls aligned with frameworks such as ICD 503 and NIST 800-53.
• Experience coordinating with ISSMs, ISSEs, System Owners, SCAs, and Authorizing Officials.
• Strong communication and stakeholder engagement skills.
• Experience supporting large-scale government cybersecurity programs.

Desired Qualifications

• Experience supporting cloud-native or DPaaS environments.
• Experience implementing Zero Trust architectures and security principles.
• Demonstrated experience leading cybersecurity initiatives across large enterprise programs.
• Prior experience managing or mentoring cybersecurity teams.
• Experience supporting intelligence community or classified environments.
• Strong understanding of identity, segmentation, flow control, and data protection architectures.
• Advanced knowledge of federal security authorization and continuous monitoring processes.

Education Requirements

• Bachelor's degree in Cybersecurity, Information Assurance, Computer Science, Information Systems, or related discipline.
• Bachelor's degree may substitute for 4 years of experience.
• Master's degree may substitute for 6 years of experience.

Certifications Required

• Security+ (or equivalent DoD 8570/8140 IAT II/IAT III certification) in active status.

Clearance

• Active TS/SCI with Active Polygraph.

Salary $125,000- 200,000

Work Location

• Annapolis Junction, MD
• Washington, DC
• Reston, VA

Physical & Work Environment Requirements

• Employees must be able to perform the essential functions of this position, with or without accommodation.
• Ability to remain stationary for extended periods while working at a computer.
• Frequently operate standard office equipment, including computers and telephones.
• Ability to communicate effectively in person, by telephone, video conference, and email.
• Occasionally move about the office and lift up to 20 pounds.
• Ability to work the assigned schedule with regular and reliable attendance.
• Ability to travel up to 10% as required.