Information System Security Officer - Senior

In support of a challenging, critical, and rewarding program that provides integrated voice, video, and data services throughout the Information Technology lifecycle, Amentum is seeking an Information System Security Officer - Senior to join our dynamic team of IT professionals dedicated to fostering a positive and collaborative work environment. You must be a critical thinker, have a strong work ethic, and be able to work independently or as a member of a team in a dynamic environment. We value candidates who are detail-oriented while also being able to think and react quickly to emerging and unique problem sets. To be successful, you must be able to rapidly adapt and learn how to operate the front and back end of new products and processes. Work Schedule: 5 Days (Mon – Fri); 8 hrs/Day; 40 hrs/wkly Essential Responsibilities: The duties and responsibilities of the Information System Security Officer - Senior include, but are not limited to the following: Generate and maintain the complete security Body of Evidence (BoE) while leading the A&A activities according to the Risk Management Framework (RMF) processes (ICD 503, CNSSI-1253, NIST 800-37, NIST 800-53, etc.) for all multiple information systems. Lead the development and maintenance of information security policies, standards, and control procedures to enable compliance with RMF. Complete Security Authorization packages, to include System Security Plans, Security Assessment Reports, POA&M summaries, and a Continuous Monitoring Plan/assessment schedule within XACTA, and present executive briefings to senior management. Conduct thorough auditing of security information and events utilizing advanced tools like Splunk and NESSUS to detect and mitigate potential threats, ensuring the integrity of the enterprise. Ensure security risk assessments are conducted as appropriate on any system upgrades, software/hardware changes, etc. Ensure security authorization boundaries are properly defined and captured in the system security plans, and that all interconnection agreements are in place and current. Ensure system security controls contain accurate implementation statements and assessment results, and that appropriate artifacts are completed to support findings; provide hands-on assistance as appropriate. Ensure POA&Ms have appropriate milestones, accurate description of the weaknesses and remediation, estimated cost and realistic due dates providing hands-on assistance to components as necessary. Maintain day-to-day security posture and continuous monitoring of all Information Systems. Review system vulnerability scans, verify implementation of DISA STIGs, and ensure other security relevant information system configuration tasks are completed. Perform test/evaluation of required technical security controls including performing certification tests and periodic inspections of information systems. Develop and conduct test procedures for verification A&A, RMF safeguards to meet customer requirements based NIST publications. Assess changes to an IS by performing periodic self-inspections, tests, and reviews of the IS program to ensure that systems are operating as authorized/accredited and that conditions have not changed; ensure corrective actions are taken for identified findings and vulnerabilities. Minimum Requirements (Knowledge, Skills, and Abilities): Must have active Top-Secret clearance with SCI or TS with the ability to acquire SCI 8 years of relevant experience In-depth knowledge of Microsoft Windows OS (client and server) and familiarity with Red Hat Enterprise Linux (RHEL). Experience with security configurations across multiple operating systems in various environments, to include Windows and Linux, utilizing Active Directory/Group Policy Experience in the development of technical documentation to include artifacts required to support Assessment and Authorization (A&A) under the Risk Management Framework Experience with XACTA, ACAS/NESSUS, Trellix, and Splunk Experience with DISA STIGs and DISA Viewer Experience with risk 2 years of knowledge and experience with NESSUS/ACAS and Trellix administration Must be able to work a 40-hour work week, normally Monday through Friday. Ability to work overtime during critical peaks and be available to meet last minute requests for overtime if needed. Ability to travel (5-10%) primarily within 75 miles. Familiarity with MS Office applications such as Excel, Word, Outlook, SharePoint, Project, and Visio. Exceptional attention to detail; excellent verbal and written communication skills; strong critical thinking, organizational, time-management, and problem-solving skills. Ability to work both independently and as part of a team in a dynamic environment. Security Clearance Required: Must have active Top-Secret clearance with SCI or TS with the ability to acquire SCI Minimum Education: Bachelor’s degree in IT related field Minimum Years of Experience: 8 years of relevant experience Required Certifications: Must possess or be able to obtain one of the following 8140 IAT Level II or III baseline certifications before start date: Level II certs include – CCNA Security, CySA+, CND, Security+ CE Level III certs include – CASP CE, CCNP Security, CISA, CISSP (or Associate) Preferred Qualifications: Previous supervision and/or participation with Cybersecurity Assessments and Authorizations Familiarity and the ability to aid with the cybersecurity tools such as ForeScout, Ivanti, and Trellix Other Responsibilities: Safety - Amentum enforces a safety culture whereby all employees have the responsibility for continuously developing and maintaining a safe work environment. As appropriate, each employee is responsible for completing all training requirements and fulfilling all self-aid/buddy aid responsibilities, participating in emergency response tasks and serving on safety committees and teams. Quality - Quality is the foundation for the management of our business and the keystone to our goal of customer satisfaction. It is our policy to consistently provide services that meet customer expectations. Accordingly, each employee must conform to the Amentum Quality Policy and carry out job activities in compliance with applicable Amentum Quality System documents and customer contracts. Each employee must read and understand his/her Quality Management and Customer Satisfaction responsibilities. Procedure Compliance - Each employee must read, understand and implement the general and specific operational, safety, quality and environmental requirements of all plans, procedures and policies pertaining to his/her job. Qualified applicants will receive consideration for employment without regard to race, color, religion, sex, national origin, sexual orientation, gender identity, disability or protected veteran status. #javelin Compensation Details: 160000 The compensation range or hourly rate listed for this position is provided as a good-faith estimate of what the company intends to offer for this role at the time this posting was issued. Actual compensation may vary based on factors such as job responsibilities, education, experience, skills, internal equity, market data, applicable collective bargaining agreements, and relevant laws. Benefits Overview: Our health and welfare benefits are designed to support you and your priorities. Offerings include: Health, dental, and vision insurance Paid time off and holidays Retirement benefits (including 401(k) matching) Educational reimbursement Parental leave Employee stock purchase plan Tax-saving options Disability and life insurance Pet insurance Note: Benefits may vary based on employment type, location, and applicable agreements. Positions governed by a Collective Bargaining Agreement (CBA), the McNamara-O'Hara Service Contract Act (SCA), or other employment contracts may include different provisions/benefits. Original Posting: 06/09/2026 - Until Filled Amentum anticipates this job requisition will remain open for at least three days, with a closing date no earlier than three days after the original posting. This timeline may change based on business needs. Amentum is proud to be an Equal Opportunity Employer. Our hiring practices provide equal opportunity for employment without regard to race, sex, sexual orientation, pregnancy (including pregnancy, childbirth, breastfeeding, or medical conditions related to pregnancy, childbirth, or breastfeeding), age, ancestry, United States military or veteran status, color, religion, creed, marital or domestic partner status, medical condition, genetic information, national origin, citizenship status, low-income status, or mental or physical disability so long as the essential functions of the job can be performed with or without reasonable accommodation, or any other protected category under federal, state, or local law. Learn more about your rights under Federal laws and supplemental language at Labor Laws Posters. Welcome back! We encourage you to check on the status of your current job applications with us. You can also search for a list of our current job openings and see if there are any new positions that might be a good fit for you. Thank you for continued interest in employment with Amentum. For more than 100 years, Amentum has tackled the world’s toughest challenges to deliver agile and steadfast solutions to the U.S. government and its allies. With more than 50,000 employees on all seven continents and in more than 60 countries, Amentum delivers a broad range of operational support services to meet the critical needs of our clients. Our headquarters are in Chantilly, VA. Find us online at If you need a reasonable accommodation for any part of the employment process, please contact us by email at View email address on click.appcast.io and let us know the nature of your request and your contact information. Requests for accommodation will be considered on a case-by-case basis. 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