Senior Information Systems Security Engineer (ISSE)

Purpose and Impact:

Are you interested in using your skills to help shape the Cyber, Security, & Intel space? If so, look no further. Amentum is seeking a Senior Information Systems Security Engineer (ISSE) to join our team of passionate individuals at Fort Meade, MD. In this role you will support challenging, mission-critical projects that make a direct impact on the Nation’s security and intelligence mission.

In support of DISA, Amentum’s Intel and Cyber Division is expanding a proven team of highly skilled engineers and architects to support a program that provides critical IT capabilities to the Department of Defense. This team is committed to engineering, assembling, integrating, deploying, and sustaining an innovative IT enterprise solution.

Our team delivers secure, mission-critical capabilities where system integrity and rapid deployment are paramount. We are seeking a Senior Information Systems Security Engineer (ISSE) who combines meticulous technical discipline with strategic foresight. In this role, you will lead efforts to establish and maintain robust baselines in a rapidly evolving operational environment. Success requires the ability to navigate complex, unique technical challenges independently while fostering collaborative solutions across integrated teams. To excel, you must possess a proactive learning mindset and the agility to rapidly master and govern the integration of next-generation systems and services.

Work Schedule: 8 Hours per day, Monday thru Friday

Essential Responsibilities:

The duties and responsibilities of the Senior Information Systems Security Engineer (ISSE) include but are not limited to the following:

The Senior ISSE leads the design, integration, and assessment of security architectures for information systems that process, store, and transmit classified and sensitive intelligence information. The incumbent applies systems security engineering principles throughout the full system lifecycle, ensures compliance with Intelligence Community (IC) and national security policy, and advises program leadership and Authorizing Officials (AOs) on risk. This is a senior technical role with significant independence, mentoring responsibility, and influence over enterprise security decisions.

Key Responsibilities:

Develop and review security architectures, designs, and requirements for classified enclaves, cross-domain solutions, cloud environments, and mission applications.

• •Integrate security controls into the system development lifecycle, including DevSecOps pipelines, so that security is built in rather than bolted on.
• •Evaluate emerging technologies (zero trust, cloud services, AI/ML tools, containerization) for security implications and recommend risk-informed adoption strategies.

Define and validate security requirements traceable to mission needs, threat models, and applicable controls.

Lead system categorization, control selection and tailoring, implementation, assessment, and continuous monitoring under the Risk Management Framework (RMF) as implemented by the IC.

Prepare and maintain authorization packages, including System Security Plans, Security Assessment Reports, Plans of Action and Milestones (POA&Ms), and risk assessments.

Brief Information System Security Managers (ISSMs), Authorizing Officials, and program leadership on residual risk and recommended mitigations.

Support reciprocity and inheritance of controls across IC elements and accrediting bodies.

Analyze vulnerability scan results, configuration baselines (STIGs/SCAPs), and penetration test findings, and drive remediation with system owners and engineering teams.

Support incident response, including technical analysis, root-cause determination, and lessons-learned integration into system designs.

Review change requests and configuration changes for security impact.

Support audits, inspections, and security reviews by oversight bodies.

Interpret and apply IC and national policy, including ICD 503, ICD 705 and its technical specifications, CNSSI 1253, NIST SP 800-37/53/53A, and applicable agency directives.

Participate in configuration control boards, architecture review boards, and security working groups.

Coordinate with counterintelligence, physical security, supply chain risk management, and cross-domain teams.

• •Mentor junior and mid-level ISSEs and security analysts.
• •Serve as a technical authority and escalation point for complex or ambiguous security issues.
• •Ability to translate complex technical risk into clear, actionable guidance for non-technical decision makers.
• •Strong written and oral communication skills, including producing high-quality technical documentation.
• •Sound judgment and the ability to balance mission needs against security requirements

Contribute to the development of standards, templates, and best practices.

Work Environment, Physical Demands, and Mental Demands:

Employee will work in a SCIF on a daily basis.

Employee may also be required to work in a datacenter environment for specified periods of time.

Minimum Requirements (Knowledge, Skills, and Abilities):

• •Experience supporting classified networks, cross-domain solutions, or multi-enclave environments.
• •Experience with cross-domain solutions, classified cloud environments (e.g., C2E/commercial cloud for IC), or zero trust implementation.
• •Familiarity with automation and scripting (Python, PowerShell, Ansible) and infrastructure-as-code security.
• •Experience with SIEM, vulnerability management, and continuous monitoring tooling (e.g., ACAS/Nessus, Splunk, eMASS or agency equivalent).
• •Expert knowledge of information systems security principles, defense-in-depth, and threat modeling.

Familiarity with ACAS, STIG Viewer, SCAP, and Assured Compliance tools.

Experience supporting ATO packages for cloud environments (e.g., C2S/commercial cloud for classified workloads).

• •Familiarity with IC-specific tools and processes for reciprocity and enterprise authorization.
• •Experience briefing AOs, program managers, and senior leadership.

Strong understanding of security control families and how to interpret implementation, inheritance, and assessment procedures.

Ability to translate technical findings into clear risk statements.

Excellent written communication, with a strong attention to detail in documentation.

Ability to manage multiple packages and competing deadlines.

Sound judgment when handling classified and sensitive information.

• •Ability to work independently and within cross-functional teams.
• •Hands-on experience managing system records, controls, artifacts, and POA&Ms in eMASS.
• •Working knowledge of the RMF, NIST SP 800-37, 800-53, and 800-53A, CNSSI 1253, and ICD 503.
• •Thorough knowledge of IC and national security information system policy, including CNSS issuances and agency directives.
• •Skill in assessing risk and applying technical, operational, and management controls.
• •Ability to translate policy into practical implementation guidance for system administrators.
• •Ability to work independently, manage multiple systems and deadlines, and exercise sound judgment in handling classified information.

Security Clearance Required:

Must have active Top Secret clearance with SCI eligibility

Minimum Education:

Bachelor's degree in cybersecurity, computer science, engineering, or a related field, plus [8-12] years of relevant experience (additional experience may substitute for education). Additional experience may substitute for a degree or equivalent professional experience (typically 4 additional years in lieu of degree).

Minimum Years of Experience:

• •At least [5] years of experience performing ISSE or equivalent security engineering duties in classified or IC environments.
• •Demonstrated experience executing the RMF and producing authorization artifacts for national security systems.

Working knowledge of network security, operating system hardening (Wind