**Description** Leidos Defense is seeking a mission-driven **Computer Network Defense (CND) Security Engineer** to join our elite team supporting a key Department of Defense (DoD) customer. Based onsite in Suitland, MD, this role is ideal for someone who thrives in fast-paced environments, enjoys solving tough cyber challenges, and is ready to take on a pivotal role in safeguarding national security systems. As a trusted cyber defense leader, you’ll work alongside some of the most driven and creative minds in the field—system administrators, network engineers, and cyber specialists—protecting cutting-edge IT infrastructures from internal and external threats. **What You’ll Do** + Analyze and monitor threat events using tools such as McAfee/Trellix ePO, Splunk Enterprise, Palo Alto Firewalls/IDPS, and RSA Authentication Manager. + Investigate endpoint alerts—malware, viruses, rogue systems, removable media—and build custom Splunk dashboards for actionable insight. + Conduct regular ACAS scans and support vulnerability assessments using Tenable tools. + Apply and update STIGs, perform SCAP scans, and manage patching across VMware ESXi, Windows Server, Windows 10, and Ubuntu Linux environments. + Contribute to documentation, including Concepts of Operations, Implementation Plans, Risk Management Framework packages, and analyst user guides. + Research and evaluate emerging technologies for cyber defense applicability. **Basic Qualifications** + Bachelor’s degree and 8+ years of experience or a Master’s degree and 6+ years of experience. Additional experience, training, and/or certifications may be substituted in lieu of a degree. + **Active DoD Top Secret/SCI clearance.** + **DoD 8570 IAT Level II certification** (e.g., Security+ CE) or ability to obtain within 30 days of hire. + Minimum of 3 years in CND roles within DoD/IC environments. + Strong background in cyber tool integration (e.g., Splunk, McAfee/Trellix, Tenable, Palo Alto). + Deep knowledge of RMF processes, vulnerability assessments, and endpoint security best practices. + Experience in deploying, patching, and configuring RedHat Enterprise Linux based security scanners such as Tenable Security Center. **Preferred Qualifications** + Experience with VMware ESXi + Mastery of Tenable Nessus/ACAS and STIG compliance + RedHat-based security scanner deployment know-how Join us at Leidos Defense and become part of a mission-first team redefining what's possible in cyber defense. If you’re ready to engineer the future of national security—let’s talk. NITESONI EIO2024 **Original Posting:** July 1, 2025 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. **Pay Range:** Pay Range $104,650.00 - $189,175.00 The Leidos pay range for this job level is a general guideline onlyand 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. REQNUMBER: R-00161933 All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability or veteran status. Leidos will consider qualified applicants with criminal histories for employment in accordance with relevant Laws. Leidos is an equal opportunity employer/disability/vet.