Information Systems Security Engineer (Top Secret)

About the role

MANTECH, a defense contractor since 1968, is hiring an Information Systems Security Engineer (ISSE) in Chantilly, VA, a full-time onsite position. The ISSE supports the Risk Management Framework (RMF), security engineering and cybersecurity lifecycle, focusing on security control design and implementation, system hardening, technical remediation, continuous monitoring and security stack operations, with an emphasis on Linux and real-time operating systems (RTOS) and supporting knowledge of Windows.

Key responsibilities

• Assist with or lead the design and integration of technical security controls into hardware, software and networking architectures throughout the SDLC
• Work in a security engineering team implementing and maintaining compliant security architectures
• Support RMF execution and system categorization with authorization boundaries, network diagrams, inventories, data flow documentation and cryptographic mapping
• Configure, harden, analyze logs and remediate Linux and RTOS systems, enforcing DISA STIGs via automated scripting
• Operate and maintain Nessus vulnerability scanners and collaborate with ISSOs on remediation
• Deploy and troubleshoot Trellix endpoint security tools to enforce media/device control and host-based defenses
• Maintain enterprise log ingestion and SIEM platforms such as Splunk or ELK for centralized auditing
• Maintain RMF artifacts in eMASS, including the SSP, POA&M and technical evidence for Authorizing Official decisions

Required profile

• Bachelor's degree in IT, Computer Science, Cybersecurity, Computer Engineering or related field with 2+ years of cybersecurity, system administration or RMF experience; or GED with 6+ years of equivalent experience
• 2+ years of hands-on Linux hardening and troubleshooting, with exposure to RTOS (e.g., QNX, VxWorks) or Windows
• Active DoD 8570/8140 IAT Level II certification (e.g., CompTIA Security+, CySA+, CISSP)
• Current or active Top Secret security clearance
• Ability to sit stationary 50% of the time and communicate accurately with colleagues, management and customers

Required skills

• Nessus and Trellix
• eMASS
• Scripting with Bash, Python or PowerShell
• Preferred: Splunk, ELK, PL2/PL3 baselines, Ansible/Puppet/Chef, CompTIA Linux+ or CASP+

What we offer

• Projected pay of $91,600 to $153,800 depending on experience, location and contract wage determination
• Health insurance, life insurance, paid time off, holiday pay, disability coverage, retirement and savings plans, learning and development and wellness programs