Security Control Assessor

Main Sail LLC; Oak Ridge (TN); On-site; USD 85,000 - 120,000; Full time

Job summary

Main Sail LLC seeks experienced Security Control Assessors to support cybersecurity and accreditation for a National Nuclear Security client in Oak Ridge, TN. The role focuses on implementing and maintaining security controls, preparing SSPs/POA&Ms, and ensuring continuous monitoring and timely remediation.

Candidates should meet DoE Q or DoW TS clearance requirements and possess strong knowledge of NIST SP 800-37/800-53.

Qualifications

• Level 3 requires Bachelor's Degree with 2-5 years' experience or Associate Degree with 5-10 years' experience.
• Level 4 requires Master's Degree with 2-5 years' experience or Bachelor's Degree with 5-10 years' experience or Associate Degree with 10-15 years' experience.
• Level 5 requires Master's Degree with 5-10 years' experience or Bachelor's Degree with 10-15 years' experience or Associate Degree with 15-20 years' experience.
• Firm understanding of NIST SP 800-37 and NIST SP 800-53; CNSSI 1253 experience a plus.
• Requires current active DoE Q or DoW TS clearance.

Responsibilities

• Implements and maintains security controls aligned with baselines and requirements.
• Supports system authorization activities and development of SSPs and POA&Ms.
• Monitors security posture, identifies risks, vulnerabilities, and gaps.
• Tracks and manages POA&Ms and coordinates remediation with stakeholders.
• Assesses security impact of changes and supports configuration/change management.
• Supports continuous monitoring activities including vulnerability management and reporting.
• Serves as a security liaison between system teams, cybersecurity operations, and governance bodies.
• Prepares systems for security assessments, audits, and Authorizing Official reviews.

Skills

Security controls

NIST SP 800-37

NIST SP 800-53

Configuration management

Vulnerability management

Governance liaison

Education

Bachelor's Degree

Associate Degree

Master's Degree

Job description

Candidates must be a United States Citizen (no dual status) per contract requirements.

Main Sail is seeking experienced Security Control Assessors to support cybersecurity and accreditation operations for a National Nuclear Security client located in Oak Ridge TN.

Responsibilities:

• Implements and maintains security controls aligned with approved baselines and organizational requirements.
• Supports system authorization activities, including the development and maintenance of security documentation such as System Security Plans (SSPs) and Plans of Action and Milestones (POA&Ms).
• Monitors system security posture and identifies risks, vulnerabilities, and compliance gaps.
• Tracks and manages POA&Ms and coordinates remediation activities with system stakeholders.
• Assesses the security impact of system changes and supports configuration and change management processes.
• Supports continuous monitoring activities, including vulnerability management and security reporting.
• Serves as a security liaison between system teams, cybersecurity operations, and governance bodies.
• Prepares systems for security assessments, audits, and Authorizing Official reviews.

Required Experience:

• Level 3: Bachelor's Degree w/ 2-5 yrs responsibilities experience; or Associates Degree w/ 5-10 yrs experience.
• Level 4: Master's Degree w/ 2-5 yrs responsibilities experience; or Bachelor's Degree w/ 5-10 yrs experience; or Associates Degree w/ 10-15 yrs experience.
• Level 5: Master's Degree w/ 5-10 yrs responsibilities experience; or Bachelor's Degree w/ 10-15 yrs experience; or Associates Degree w/ 15-20 yrs experience.
• Firm understanding of NIST SP 800-37 and NIST SP 800-53; CNSSI 1253 experience a plus.
• Requires current active DoE Q; or DoW TS.

Location: Must reside within 50 miles of Y-12 Site, Oak Ridge TN. Period: 09/2026 - 09/2027 with possible extensions.