Vulnerability Management & ACAS Administrator

Leidos is seeking an Vulnerability Management & ACAS Administrator to support large-scale operations on a high-profile Department of War contract in Fort Belvoir, VA. The I3TS program provides enterprise-wide IT support to enable the Defense Threat Reduction Agency’s Information Management & Technology Directorate to consolidate, modernize, and continuously improve delivery of IT services and mission capabilities to internal and external mission partners operating in CONUS and OCONUS locations.

The selected candidate will serve as the primary ACAS subject-matter expert and technical lead for the program’s vulnerability scanning capability across NIPRNet, SIPRNet, and the Joint Worldwide Intelligence Communications System (JWICS). This position requires an experienced, independent professional who can oversee day-to-day ACAS operations, maintain scanner health and coverage, analyze findings, produce actionable reporting, and coordinate remediation activities with system owners and technical teams.

Primary Responsibilities:

• Serve as the primary technical lead and subject-matter expert for Assured Compliance Assessment Solution (ACAS) and Nessus vulnerability-scanning operations across NIPRNet, SIPRNet, and JWICS environments.
• Administer, operate, maintain, and troubleshoot ACAS/Nessus infrastructure, including scanners, scan configurations, scan schedules, policies, plugins, credentials, and associated management components.
• Ensure ACAS scanning capability, asset coverage, scanner health, and vulnerability-data quality are maintained across all supported environments.
• Plan, coordinate, and execute authenticated and unauthenticated vulnerability scans in accordance with approved schedules, operational requirements, and maintenance windows.
• Analyze scan results; validate findings; identify false positives, duplicate findings, and scan-quality issues; and assess the potential impact to supported systems and mission operations.
• Prioritize vulnerabilities based on severity, operational impact, exploitability, asset criticality, and applicable remediation timelines.
• Coordinate with system administrators, network engineers, endpoint-security personnel, and system owners to facilitate vulnerability remediation and verify closure.
• Track vulnerabilities, remediation actions, exceptions, findings, and status in approved tracking systems.
• Develop and maintain vulnerability-management metrics, dashboards, trend analysis, and recurring reports for technical personnel, program leadership, and customer stakeholders.
• Identify and resolve ACAS coverage gaps, credentialed-scan failures, connectivity issues, scanner performance issues, and asset-inventory discrepancies.
• Support Security Technical Implementation Guide (STIG) compliance activities by correlating ACAS findings with hardening requirements and remediation actions.
• Develop and maintain ACAS standard operating procedures, operating instructions, scan procedures, troubleshooting guides, and knowledge articles.
• Coordinate ACAS maintenance, upgrades, configuration changes, and technical support activities with applicable infrastructure, network, endpoint, and cybersecurity teams.
• Provide technical guidance to leadership and stakeholders on ACAS capabilities, vulnerability trends, remediation priorities, and operational risk.
• Work independently to manage competing requirements and meet short-, mid-, and long-term vulnerability-remediation timelines.

Basic Qualifications:

• Bachelor’s degree and 7+ years of relevant cybersecurity, vulnerability management, systems administration, or information assurance experience; or additional relevant experience in lieu of a degree.
• At least 7 years of hands-on experience serving as an ACAS/Nessus subject-matter expert in a large enterprise or Department of War environment.
• Demonstrated experience administering and operating ACAS/Nessus infrastructure, including scanner deployment, configuration, health monitoring, scan-policy administration, plugin management, credentialed scanning, troubleshooting, and reporting.
• Experience managing vulnerability scanning operations across multiple security domains, including NIPRNet, SIPRNet, and JWICS or comparable enterprise environments.
• Experience analyzing vulnerability findings, validating scan results, identifying false positives, prioritizing remediation, and verifying closure.
• Experience developing vulnerability-management reports, metrics, dashboards, and leadership-level status products.
• Experience coordinating remediation efforts with system administrators, network teams, endpoint-security teams, and system owners.
• Working knowledge of Microsoft Windows, Linux, virtualization technologies, networking concepts, and enterprise endpoint environments.
• Working knowledge of STIG compliance, SCAP Compliance Checker (SCC), STIG Viewer, secure configuration baselines, and security-hardening practices.
• Must meet DoD 8570.01-M Information Assurance Technical (IAT) Level II baseline certification requirements. Acceptable certifications include CompTIA Security+ CE or a higher-level certification that satisfies the IAT Level II requirement. Must also meet applicable DoD 8140 Cyberspace Workforce Qualification Program requirements for the assigned DoD Cyber Workforce Framework work role(s), as required by the contract and customer.
• Must currently possess and maintain an active Top Secret/Sensitive Compartmented Information (TS/SCI) clearance.
• Strong written, verbal, organizational, analytical, and problem-solving skills.
• Ability to work independently as the program’s primary ACAS technical lead while coordinating effectively with cross-functional technical teams.

Preferred Qualifications:

• Tenable Assured Compliance Assessment Solution (ACAS) 201 certification.
• Experience integrating or correlating ACAS data with asset-management, endpoint-security, configuration-management, ticketing, or vulnerability-tracking tools.
• Experience using Tanium, Trellix, Microsoft Defender for Endpoint, or comparable endpoint-security and endpoint-management platforms to support vulnerability remediation and asset validation.
• Experience developing automated reports, dashboards, or data-analysis products using PowerShell, Python, SQL, or similar tools.
• Experience supporting vulnerability exception management, risk acceptance workflows, Plans of Action and Milestones, and remediation governance.
• Relevant Tenable, vulnerability-management, Microsoft, Linux, or cybersecurity certifications.

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Original Posting:

October 19, 2026

Pay Range:

Pay Range $107,900.00 - $195,050.00

The Leidos pay range for this job level is a general guideline only and not a guarantee of compensation or salary. Additional factors considered in extending an offer include (but are not limited to) responsibilities of the job, education, experience, knowledge, skills, and abilities, as well as internal equity, alignment with market data, applicable bargaining agreement (if any), or other law.