Information System Security Engineer

MANTECH; Chantilly (VA); On-site; USD 90,000 - 130,000; Full time

Job summary

MANTECH seeks a motivated Information Systems Security Engineer to join our team in Chantilly, VA. This onsite role may also be available in San Diego, CA. You will design and integrate security controls, support RMF, maintain Nessus and SIEM tools, and ensure compliance across complex platforms.

The ideal candidate holds DoD 8570/8140 IAT Level II, hands-on experience with Linux/RTOS, scripting, and eMASS, and can work within an ISSO-driven environment.

Qualifications

• Bachelor's degree in IT, Computer Science, Cybersecurity, Computer Engineering, or related field with 2+ years of relevant cybersecurity, RMF experience; OR High School Diploma/GED with 6+ years of cybersecurity engineering, RMF experience.

Responsibilities

• Assist with design and integration of security controls into system architectures throughout the SDLC.
• Work within a technical security engineering team to implement compliant security architectures across complex platforms.
• Support RMF execution and system categorization with documentation and mapping.
• Configure, harden, and remediate Linux and RTOS environments while enforcing DISA STIGs via scripts.
• Operate and maintain Nessus scanners and coordinate with ISSOs on remediation.

Skills

RMF

Nessus

Scripting

SIEM

Trellix

eMASS

Education

Bachelor's degree in IT/CS/Cybersecurity/Engineering

HS Diploma + 6+ years experience

Tools

Nessus

Trellix

Splunk/ELK

eMASS

Job description

MANTECH seeks a motivated, career and customer-oriented Information Systems Security Engineer to join our team in Chantilly, VA. This position will be onsite. This role can optionally be in San Diego, CA.

Responsibilities Include But Are Not Limited To

• Assist with or lead the design and integration of technical security controls into system hardware, software, and networking architectures throughout the SDLC
• Work within a technical security engineering team responsible for implementing and maintaining compliant security architectures across complex platforms
• Support RMF execution and system categorization by defining authorization boundaries with network diagrams, hardware/software inventories, data flow documentation, and cryptographic mapping
• Perform hands-on configuration, hardening, log analysis, and remediation on Linux and RTOS environments while enforcing DISA STIGs via automated scripting
• Operate, configure, and maintain Nessus vulnerability scanners and collaborating with ISSOs to analyze scan outputs and determine remediation pathways
• Deploy, configure, and troubleshoot Trellix endpoint security tools across host endpoints to enforce strict media/device control policies and host-based defenses
• Support and maintain enterprise log ingestion and SIEM platforms such as Splunk or Elastic (ELK) to support centralized auditing and continuous monitoring
• Maintain accurate RMF artifacts in eMASS, including the System Security Plan (SSP), POA&M, and supporting technical evidence to support Authorizing Official (AO) decisions

Minimum Qualifications

• Bachelor's degree in IT, Computer Science, Cybersecurity, Computer Engineering, or related field with 2+ years of relevant cybersecurity, system administration or RMF experience; OR High School Diploma/GED with 6+ years of cybersecurity engineering, system administration, or RMF experience
• 2+ years of hands-on experience configuring, hardening, or troubleshooting Linux operating systems, with exposure to RTOS (e.g., QNX, VxWorks) or Windows environments
• Active DoD 8570/8140 IAT Level II certification, e.g., CompTIA Security+ CE, CySA+, SecurityX, CISSP
• Hands-on experience or working knowledge of Nessus vulnerability scanners and Trellix endpoint security tools
• Experience or training with eMASS
• Familiarity with scripting languages (Bash, Python, or PowerShell) for basic task automation, configuration management, or compliance checking

Preferred Qualifications

• Hands-on experience installing, configuring, or operating Splunk, Elasticsearch/Kibana (ELK), or another enterprise log analytics platform
• Understanding of PL2 vs. PL3 security baselines, trust boundaries, and segmentation concepts
• Active industry certifications such as CompTIA Linux+, CGRC, or IAT Level III SecurityX (CASP+), or CISSP
• Experience integrating security into the SDLC or utilizing configuration management tools (Ansible, Puppet, Chef) for STIG automation

Clearance Requirements

• Must have a current or active Top Secret security clearance

Physical Requirements

• Must be able to remain in a stationary position 50% of the time
• Needs to occasionally move about inside the office to access file cabinets, office machinery, etc.
• Frequently communicates with co-workers, management, and customers, and must be able to exchange accurate information in these situations