Principal Cybersecurity Engineer

Leidos is seeking a Principal Cybersecurity Engineer to help protect customer information systems, networks, and infrastructure from cyber threats and vulnerabilities. In this McLean, VA onsite role, you will support the design, implementation, and maintenance of security controls that safeguard mission systems while aligning with compliance needs across the DevSecOps lifecycle.

What you will do

• Plan, implement, manage, monitor, and upgrade security controls and tools used to protect enterprise systems and networks, including identifying opportunities to automate repeatable operations tasks.
• Design, configure, implement, troubleshoot, and maintain security technologies such as firewalls (security groups), endpoint protection tools (HBSS/Trellix, Carbon Black EDR), and SIEM platforms (Splunk).
• Monitor system and network security using SIEM capabilities such as Splunk Enterprise Security to detect, analyze, and respond to potential threats or anomalous activity.
• Support investigations and remediation for cybersecurity incidents, including system or network breaches and malware infections.
• Participate in change management processes to help ensure system changes maintain security compliance and do not introduce new vulnerabilities.
• Audit systems and configurations to verify compliance with cybersecurity policies, standards, and secure configuration baselines.
• Collaborate with engineering, development, and operations teams to integrate security controls into DevSecOps pipelines and system architectures.
• Continuously monitor security advisories, bulletins, and industry threat intelligence to stay current on vulnerabilities, threats, and trends.
• Assist with implementation and enforcement of secure system configurations and cybersecurity compliance requirements.
• Support vulnerability management by reviewing scan results, assessing risk, and coordinating remediation efforts with system owners and technical teams.

Key requirements

• Education and experience: BS degree with 12+ years of relevant experience, or MS degree with 10+ years of relevant experience (additional years may substitute for a degree).
• Clearance: Must have an active TS/SCI with a Polygraph to be considered.
• Experience implementing and managing SIEM tools such as Splunk or similar platforms.
• Experience with endpoint and network security technologies, including IDS/IPS, HBSS/Trellix, and Carbon Black EDR.
• Experience reviewing and analyzing cybersecurity event logs to identify indicators of compromise or suspicious activity.
• Experience supporting incident response plans, vulnerability management programs, risk management plans, and Plans of Action and Milestones (POA&Ms).
• Experience conducting or supporting technical cybersecurity assessments and security audits.
• Experience identifying system vulnerabilities and instances of non-compliance with cybersecurity standards and regulatory requirements.
• Experience collaborating with DevSecOps teams to review vulnerability scan results and support remediation of findings.
• Experience supporting the Risk Management Framework (RMF) authorization process by reviewing security documentation and providing risk-based recommendations related to system risk posture as part of Authority to Operate (ATO) activities.
• Ability to manage and track POA&Ms for customer-sponsored systems, coordinating with ISSOs, ISSEs, ISSMs, and Security Control Assessors (SCAs).
• Experience applying system security engineering principles across areas including system security design and lifecycle engineering, authentication and authorization, cryptography, intrusion detection, contingency planning, incident handling, auditing, configuration management, and change control.
• Professional cybersecurity certifications such as Security+, CISSP, CySA+, CEH, or GCIH.

Technologies

• Splunk, Splunk Enterprise Security
• HBSS/Trellix, Carbon Black EDR (EDR platforms)
• IDS/IPS
• Rapid7, Tenable/Nessus
• SonarQube, Fortify, Chainguard
• STIG viewers, Ansible, CloudFormation
• Python, PowerShell, React
• AWS, Oracle Cloud, GCP
• SolarWinds, Linux (Red Hat)
• DevSecOps pipelines, CI/CD security tools

Benefits

• Paid Time Off
• 11 paid Holidays
• 401K with a 6% company match and immediate vesting
• Flexible Schedules
• Discounted Stock Purchase Plans
• Technical Upskilling
• Education and Training Support
• Parental Paid Leave

Location: McLean, VA (onsite)

Pay range: USD 131,300 - 237,350 per year

Original posting date: October 14, 2026

U.S. positions notice: While subject to change based on business needs, Leidos reasonably anticipates the requisition will remain open for at least 3 days, with an anticipated close date no earlier than 3 days after the original posting date.