Information Systems Security Engineer

Description Cyber Security Engineer / ISSE - Lead Security Engineering for MissionCritical SystemsLeidos is seeking a Cyber Security Engineer / Information Systems Security Engineer (ISSE) to support a highvisibility, missionessential enterprise program. In this role, you'll apply deep security engineering expertise to design, assess, and harden complex systems while guiding them through the full Risk Management Framework (RMF) lifecycle. If you thrive at the intersection of technical engineering, cybersecurity strategy, and accreditation excellence, this is where your impact will be felt immediately.You'll collaborate with accreditation authorities, system owners, and engineering teams to ensure systems achieve and maintain Authorization to Operate (ATO) while meeting the highest security standards. What You'll DoAs a senior security engineer, you'll shape the security posture of missioncritical applications and lead the engineering of RMF artifacts across a largescale enterprise environment.Your responsibilities include:Supporting missioncritical applications through the full ATO lifecycle in alignment with customer security policiesLeading security engineering efforts and contributing to system design with a focus on secure architectureEnsuring ATO packages adhere to RMF and DoD security guidelines by working closely with technical leads, developers, and system ownersProviding expert ISSE guidance across engineering tasks and projectsDefining system functions, information types, operating environments, and security requirementsProducing security artifacts and evidence for RMF control validationReviewing and tailoring security controls to ensure adequate protectionDetermining assurance measures to meet system assurance requirementsDesigning and implementing security controls and best practices, including Zero Trust ArchitectureConducting A&A activities and coordinating with DAO representatives and security teamsCreating and updating RMF documentation and artifacts in eMASSReviewing system audit logs and taking corrective action when neededPerforming security monitoring, audits, and control assessments using enterprise tool suitesDelivering technical briefings and TEMs to communicate security concepts to nontechnical stakeholdersDeveloping security assessment criteria to ensure development teams meet A&A requirementsEnsuring compliance with encryption standards and secure communicationsStaying ahead of emerging security trends and technologies to support future mission needsMentoring team members and supporting project execution across the security engineering team Required Qualifications & SkillsYou bring deep technical expertise, strong security engineering instincts, and the ability to lead complex accreditation efforts.Active DoD TS/SCI clearanceCurrent DoD 8140compliant security certification; ability to obtain CE certification within 6 months10+ years of experience in software engineering, system design, configuration management, integration testing, or information system engineering5+ years of experience in system security analysis, secure system design, or protocol/interface standardsExperience with Assessment & Authorization (A&A) for multiple security applicationsExperience preparing SSPs, risk assessments, SOPs, and contingency plansDemonstrated experience creating and validating RMF security control evidenceExperience hardening Windows and Linux systems (ports, protocols, security groups, patching)Working knowledge of RHEL 9 and Windows Server 2019/2022Ability to work in an Agile environment using sprints and Jira boardsExperience applying Agile methodologies to security engineering workflowsProficiency with enterprise scanning tools such as Tenable, Burp Suite, Defender for Endpoint, ACAS, ESS, and TaniumStrong communication skills for both technical and nontechnical audiencesAbility to manage multiple tasks in a dynamic environment Preferred QualificationsThese skills will help you stand out:Experience with Security OnionFamiliarity with backend security analysis tools such as Suricata, Yara, Sigma, Elasticsearch, Logstash, Kibana, Elastic Fleet, PCAP, OSquery, and ZeekExperience with Splunk, Elasticsearch SIEM, and SOAR platforms Why This Role MattersAs an ISSE, you are a key architect of mission security. Your work ensures that critical systems remain secure, compliant, and resilient against evolving threats. You'll shape the security engineering strategy for a major enterprise program while mentoring others and driving innovation across the organization.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:March 26, 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.Pay Range:Pay Range $107,900.00 - $195,050.00The 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.About LeidosLeidos 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 $16.7 billion for the fiscal year ended January 3, 2025. For more information, visit www.Leidos.com.Pay and BenefitsPay 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. More details are available at www.leidos.com/careers/pay-benefits.Securing Your DataBeware of fake employment opportunities using Leidos' name. Leidos will never ask you to provide payment-related information during any part of the employment application process (i.e., ask you for money), nor will Leidos ever advance money as part of the hiring process (i.e., send you a check or money order before doing any work). Further, Leidos will only communicate with you through emails that are generated by the Leidos.com automated system - never from free commercial services (e.g., Gmail, Yahoo, Hotmail) or via WhatsApp, Telegram, etc. If you received an email purporting to be from Leidos that asks for payment-related information or any other personal information (e.g., about you or your previous employer), and you are concerned about its legitimacy, please make us aware immediately by emailing us at LeidosCareersFraud@leidos.com.If you believe you are the victim of a scam, contact your local law enforcement and report the incident to the U.S. Federal Trade Commission.Commitment to Non-DiscriminationAll 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.