Information Systems Security Engineer (ISSE) Linux/RHEL Sterling, VA, US

CACI International; Sterling (VA); On-site; USD 87,000 - 182,000; Full time

Job summary

CACI International Inc in Sterling, VA is seeking a Linux-focused Information Systems Security Engineer (ISSE) to support security, accreditation, and continuous monitoring of mission-critical systems in classified environments. You will apply RMF, implement DISA STIGs, and harden Red Hat Enterprise Linux.

The role requires hands-on Linux administration, scripting in Bash or Python, and collaboration with engineers across SDLC to ensure secure configurations and ATO readiness.

Qualifications

• 5+ years of cybersecurity engineering, information assurance, or Linux administration.
• 2+ years hands-on Linux administration, preferably RHEL 8/9.
• Experience implementing Linux DISA STIGs and vulnerability remediation.
• Knowledge of RMF, ICD 503, NIST 800-53, and ATO lifecycle.
• DoD 8570 IAT Level II certification or equivalent required.
• Active TS/SCI with eligibility.

Responsibilities

• Perform hands-on security engineering, configuration, and hardening of RHEL systems.
• Implement and maintain DISA STIG compliance; run SCAP scans and fix findings.
• Troubleshoot SELinux, SSH, permissions, services, and network configs.
• Lead A&A activities to achieve and maintain ATO under RMF.
• Develop security docs: SSPs, SARs, SCTMs, and POA&Ms.
• Collaborate across SDLC with engineers to embed security requirements.
• Develop Bash or Python scripts to automate security tasks.

Skills

Linux System Admin

DISA STIGs

SCAP Scans

RMF ATO

SELinux

Bash/Python

DoD 8570 IAT II

Security clearance

RHEL 8/9

Vulnerability remediation

Education

Bachelor's degree in a technical discipline

DoD 8570 IAT II certification

RHCSA/RHCE certification

Tools

Puppet

Ansible

Red Hat Satellite

IdM/FreeIPA

ACAS

Nessus

SCAP Compliance Checker

Git/GitLab

Job description

## Information Systems Security Engineer (ISSE) Linux/RHELSterling, VA, USApply NowFind out how well you match with this jobJob ID: 334367Job Title: Information Systems Security Engineer (ISSE) Linux/RHELJob Category: SecurityTime Type: Full timeMinimum Clearance Required to Start: TS/SCIEmployee Type: RegularPercentage 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. **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. *Desired:* 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+-**What You Can Expect:****A culture of integrity.**At CACI, we place character and innovation at the center of everything we do. As a valued team member, you’ll be part of a high-performing group dedicated to our customer’s missions and driven by a higher purpose – to ensure the safety of our nation.**An environment of trust.**CACI values the unique contributions that every employee brings to our company and our customers - every day. You’ll have the autonomy to take the time you need through a unique flexible time off benefit and have access to robust learning resources to make your ambitions a reality.**A focus on continuous growth.**Together, we will advance our nation's most critical missions, build on our lengthy track record of business success, and find opportunities to break new ground — in your career and in our legacy.**Pay Range**:There are a host of factors that can influence final salary including, but not limited to, geographic location, Federal Government contract labor categories and contract wage rates, relevant prior work experience, specific skills and competencies, education, and certifications. Our employees value the flexibility at CACI that allows them to balance quality work and their personal lives. We offer competitive compensation, benefits and learning and development opportunities. Our broad and competitive mix of benefits options is designed to support and protect employees and their families. At CACI, you will receive comprehensive benefits such as; healthcare, wellness, financial, retirement, family support, continuing education, and time off benefits.The proposed salary range for this position is:$86,600 - $181,800*CACI is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, pregnancy, sexual orientation, age, national origin, disability, status as a protected veteran, or any other protected characteristic.*