Tenable RHEL ACAS Administrator

Position Summary

Leidos has a current job opportunity for a Tenable RHEL ACAS Administrator on the DISA GSM-O program in Alexandria, VA. An active Secret Security Clearance is required prior to start. This position serves as a member of the Tenable ACAS team responsible for operating and maintaining the DISA J6 Pentagon’s Assured Compliance Assessment Solution (ACAS) program. This position supports timely and accurate scanning and reporting per DISA J6 Pentagon and DoD policies and orders. Activities that this position will execute include system administration for all Tenable ACAS Red Hat Enterprise Linux (RHEL) servers, performing systems analysis, modifying / updating, troubleshooting Tenable applications based on results of analysis, deployment of application and tools, performing testing of deployed application and tools, and communicating updates to Tenable ACAS Lead and customers as required.

Responsibilities

• Serve as an integral member of a team of Tenable specialists supporting various organizations across the National Capital Region
• Complete the following key functions for Tenable deployments across DISA J6 Pentagon’s area of responsibility: Manage the RHEL servers that are part of the Tenable ACAS for DISA J6 Pentagon.
• Provide performance tuning to systems and troubleshoot Tenable components which span a large and complex environment
• Provide solution engineering support to ensure systems and components meet current and future standards
• Install updates to Tenable software as released and in compliance with STIG requirements
• Deploy, maintain, and perform tuning of Tenable scanners to meet current and future needs
• Deploy, maintain, and perform tuning of Tenable Nessus Managers and Nessus Agents to meet current and future needs
• Develop / create, deploy, and manage Tenable scan configurations
• Conduct scans and provide detailed reporting to the DISA J6 Pentagon leadership as well as scanned organizations
• Ensure that the ACAS scanners and Security Center are operational and reporting properly
• Assist customers in resolving ACAS issues, make recommendations as needed
• Perform monthly vulnerability scans and create repositories, queries, and dashboards as necessary to ensure vulnerability report information is available
• Investigate false positives or potentially confusing scan data results
• Develop tracking mechanism for false positives and track false positives until the finding is corrected; provide results upon resolution

Basic Qualifications

• Bachelor's degree and 12+ years of prior IT experience including experience working with RHEL OS, Tenable Security Center and Tenable Nessus agents within the DoD environment. Additional work experience or Cyber courses/certifications may be substituted in lieu of degree.
• Active Secret clearance or higher (program can support up to TS/SCI)
• DoD 8570 IAT II certification is required prior to start.
• Current RHEL certification or ability to obtain certification within 6 months of start date.
• Experience running ACAS on Red Hat Enterprise Linux (RHEL)
• Hands-on experience with general RHEL administration and troubleshooting
• Demonstrated experience with multiple network security zones, subnetting, VRFs, and VLANs
• Motivated self-starter with strong written and verbal communication skills, and the ability to create complex technical reports on analytic finding.
• Strong analytical and troubleshooting skills.

Preferred Qualifications

• Cybersecurity experience (Protect, Detect, Respond and Sustain) within a Computer Incident Response organization.
• Advanced understanding of the life cycle of cybersecurity threats, attacks, attack vectors and methods of exploitation with an understanding of intrusion set tactics, techniques and procedures (TTPs).
• Experience with malware analysis concepts and methods.
• Motivated self-starter with strong written and verbal communication skills, and the ability to create complex technical reports on analytic findings.
• Familiarity or experience in Intelligence Driven Defense, Cyber Kill Chain methodology, and/or MITRE ATT&CK framework.

Pay and Benefits

Pay and benefits are fundamental to any career decision. That's why we craft compensation packages that reflect the importance of the work we do for our customers. Employment benefits include competitive compensation, Health and Wellness programs, Income Protection, Paid Leave and Retirement.

Securing Your Data

Leidos will never ask you to provide payment-related information at any part of the employment application process. And Leidos will communicate with you only through emails that are sent from a Leidos.com email address. If you receive an email purporting to be from Leidos that asks for payment-related information or any other personal information, please report the email to View email address on click.appcast.io.

Commitment and Diversity

All qualified applicants will receive consideration for employment without regard to sex, race, ethnicity, age, national origin, citizenship, religion, physical or mental disability, medical condition, genetic information, pregnancy, family structure, marital status, ancestry, domestic partner status, sexual orientation, gender identity or expression, veteran or military status, or any other basis prohibited by law. Leidos will also consider for employment qualified applicants with criminal histories consistent with relevant laws.

Pay Range

Pay Range $131,300.00 - $237,350.00 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.

About Leidos

Leidos Leidos is an industry and technology leader serving government and commercial customers with smarter, more efficient digital and mission innovations. Headquartered in Reston, Virginia, with 47,000 global employees, Leidos reported annual revenues of approximately $17.2 billion for the fiscal year ended January 2, 2026. For more information, visit

Company Culture

At Leidos, we outthink, outbuild, and outpace the status quo — because the mission demands it. We're not hiring followers. We're recruiting the ones who disrupt, provoke, and refuse to fail. Step 10 is ancient history. We're already at step 30 — and moving faster than anyone else dares.

Original Posting

October 28, 2026 For U.S. Positions: While subject to change based on business needs, Leidos reasonably anticipates that this job requisition will remain open for at least 3 days with an anticipated close date of no earlier than 3 days after the original posting date as listed above.