Job Title: Information Systems Security Engineer (ISSE) Linux/RHEL
Job Category: Security
Time Type: Full time
Minimum Clearance Required to Start: TS/SCI
Employee Type: Regular
Percentage of Travel Required: Up to 25%
Type of Travel: Continental US
The Opportunity
We are seeking a highly motivated, Linux-focused Information Systems Security Engineer (ISSE) to support the security, accreditation, and continuous monitoring of mission-critical systems operating within classified environments. The ideal candidate combines cybersecurity engineering expertise with hands-on Red Hat Enterprise Linux (RHEL) administration skills. This position requires an individual comfortable working directly with Linux systems to implement security controls, troubleshoot configurations, remediate vulnerabilities, and support Risk Management Framework (RMF) compliance. Working alongside systems engineers, software developers, and cybersecurity professionals, you will help design, implement, and maintain secure solutions supporting critical national security missions. This position requires onsite support 100% of the time in Sterling, VA. Domestic and international travel opportunities may be available.
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 activities 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.
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Qualifications
Required
- Required
- 5+ years of combined experience in cybersecurity engineering, information assurance, Linux systems administration, or related technical disciplines
- Minimum 2 years of hands-on Linux administration experience, preferably with RHEL 8/9
- Practical Linux command-line proficiency, including filesystem management, permissions, user administration, package management (DNF/YUM), 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 (Security+ CE, CySA+, SSCP, or equivalent applicable certification)
- Bachelor's degree in a technical discipline or equivalent relevant experience
- Active Top Secret clearance with SCI eligibility.
