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.
Position Summary:
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 include:
- 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.
If you're looking for comfort, keep scrolling. 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, 2026For 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.
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.
Skills Required
- Bachelor's degree and 12+ years of prior IT experience, including RHEL, Tenable Security Center, and Tenable Nessus Agents experience in a DoD environment; additional experience or cyber certifications may substitute for the degree
- Active Secret security clearance or higher
- DoD 8570 IAT II certification prior to start
- Current RHEL certification or ability to obtain certification within six months of starting
- Experience running ACAS on Red Hat Enterprise Linux
- Hands-on RHEL administration and troubleshooting experience
- Experience with multiple network security zones, subnetting, VRFs, and VLANs
- Strong written and verbal communication skills and ability to create complex technical reports
- Strong analytical and troubleshooting skills
- Cybersecurity experience within a Computer Incident Response organization
- Understanding of cybersecurity threats, attacks, exploitation methods, and intrusion set tactics, techniques, and procedures
- Experience with malware analysis concepts and methods
- Familiarity with Intelligence Driven Defense, Cyber Kill Chain methodology, or MITRE ATT&CK framework
Leidos Compensation & Benefits Highlights
The following summarizes recurring compensation and benefits themes identified from responses generated by popular LLMs to common candidate questions about Leidos and has not been reviewed or approved by Leidos.
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Healthcare Strength — Healthcare coverage is described as comprehensive, with multiple plan options, low office-visit copays in some plans, and access to mental health and wellness support tools. The availability of HSA/FSA options and employer contributions is positioned as a meaningful part of the total package.
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Retirement Support — Retirement benefits are framed as a strong component of total rewards, highlighted by a 401(k) match and immediate vesting in the standard package. The Employee Stock Purchase Plan is also presented as an additional long-term wealth-building feature.
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Wellbeing & Lifestyle Benefits — Wellbeing and lifestyle supports extend beyond core insurance, including wellness programs, fitness-related stipends, and assistance resources. Work flexibility and related perks are also included as part of the broader rewards experience.
Leidos Insights
What We Do
We Are Leidos For 50 years we have been tackling some of the biggest problems that face our nation and our world. OUR MISSION Through our culture of innovation and history of performance, we develop deep customer trust built on integrity and create enduring solutions that improve our world. Leidos is a science and technology solutions leader working to address some of the world’s toughest challenges in the defense, intelligence, homeland security, civil, and healthcare markets. The company’s 43,000 employees support vital missions for government and commercial customers. Headquartered in Reston, Va., Leidos reported annual revenues of approximately $11.09 billion for the fiscal year ended January 3, 2020. Leidos was cited for the meaningful work employees perform that is challenging, impactful, and aligned with our customers’ missions as reasons professionals want to work and stay at our company. Leidos has also been named to lists including Forbes’ Best Employers for Diversity, Forbes’ America’s Best Employers for Women, Military Times Best for Vets Employers, and Ethisphere Institute’s World's Most Ethical Companies®. Employees enjoy career enrichment opportunities available through mobility and development and experience rewarding relationships with supportive supervisors and talented colleagues and customers. Employees appreciate our flexible work environment, allowing for and encouraging a true work-life balance. Our professionals are also excited about our Employee Resource Groups, like the newly launched Collaborative Outreach with Remote and Embedded Employees (CORE), which strives to create an environment where every employee, regardless of location, feels fully engaged as a valued employee of Leidos. Your most important work is ahead.







