Information Systems Security Engineer (ISSE) Linux/RHEL

CACI•Sterling, VA

9d•Onsite

About The Position

CACI is seeking a Linux-focused Information Systems Security Engineer (ISSE) to support security, accreditation, and continuous monitoring for mission-critical systems in classified environments. The role combines cybersecurity engineering with hands-on Red Hat Enterprise Linux (RHEL) administration, including implementing security controls, troubleshooting configurations, remediating vulnerabilities, and supporting Risk Management Framework (RMF) compliance. The position works with systems engineers, software developers, and cybersecurity professionals to design, implement, and maintain secure solutions for national security missions. It requires onsite support 100% of the time in Sterling, Virginia. Domestic and international travel opportunities may be available; the job posting also states that travel of up to 25% may be required.

Requirements

At least 5 years of combined experience in cybersecurity engineering, information assurance, Linux systems administration, or related technical disciplines.
At least 2 years of hands-on Linux administration experience, preferably with RHEL 8 or 9.
Practical Linux command-line proficiency, including filesystem management, permissions, user administration, DNF/YUM package management, systemd services, log analysis, SSH, and basic network troubleshooting.
Experience implementing Linux DISA STIGs, executing SCAP scans, and performing vulnerability remediation.
Working knowledge of Linux security technologies, including SELinux, firewalld, authentication, and access controls.
Experience with Bash scripting and/or Python for system administration or security automation.
Strong understanding of RMF, ICD 503, NIST 800-53, and the ATO lifecycle.
DoD 8570/8140 IAT Level II certification, such as Security+ CE, CySA+, SSCP, or an equivalent applicable certification.
Bachelor's degree in a technical discipline or equivalent relevant experience.
Active Top Secret clearance with SCI eligibility.

Nice To Haves

Red Hat Certified System Administrator (RHCSA) or Red Hat Certified Engineer (RHCE) certification.
Experience supporting RHEL systems in classified, disconnected, or air-gapped environments.
Familiarity with Puppet, Ansible, Red Hat Satellite, or Red Hat Identity Management (IdM/FreeIPA).
Experience with ACAS, Nessus, SCAP Compliance Checker, or similar vulnerability assessment tools.
Experience with Git, GitLab, DevSecOps, and automated compliance solutions.
Experience supporting Cross Domain Solutions (CDS) or other highly secure mission systems.
Advanced cybersecurity certifications such as CISSP or CASP+.

Responsibilities

Perform hands-on security engineering, configuration, troubleshooting, and hardening of Red Hat Enterprise Linux (RHEL) systems.
Implement, validate, and maintain DISA STIG compliance, including executing SCAP scans, analyzing findings, and remediating security vulnerabilities.
Troubleshoot Linux security configurations involving SELinux, SSH, permissions, authentication, system services, and networking.
Lead and support Assessment and Authorization (A&A) activities to achieve and maintain Authorization to Operate (ATO) under the Risk Management Framework (RMF).
Develop and maintain security documentation, including System Security Plans (SSPs), Security Assessment Reports (SARs), Security Control Traceability Matrices (SCTMs), and Plans of Action and Milestones (POA&Ms).
Conduct security assessments and continuous monitoring aligned with ICD 503, NIST 800-53, CNSSI, and applicable DoD requirements.
Collaborate with systems, network, software, and DevOps engineers to integrate security requirements throughout the System Development Life Cycle (SDLC).
Evaluate system architectures, infrastructure changes, and software configurations to identify security risks and recommend mitigations.
Develop Bash or Python scripts to automate security compliance, vulnerability assessments, and routine administrative tasks.