Computer Network Defense Analyst

Leidos; Arlington (VA); On-site; USD 70,000 - 126,000; Full time

Job summary

Leidos in Arlington, VA seeks a network defense analyst to detect and respond to cybersecurity incidents. You will monitor security tools, analyze alerts, and coordinate remediation with cross-functional teams.

The role requires a TS/SCI clearance, DoDD 8140 IAT Level II certification, and strong knowledge of Windows, Linux, cloud platforms, and network security.

Qualifications

• Bachelor's degree required; 2+ years of related experience preferred.
• Active TS/SCI security clearance required for this position.
• DoDD 8140 IAT Level II (or Level III) certification (e.g., Security+ CE).
• Strong computing systems knowledge with Windows, Red Hat, Cloud (AWS, Azure), and networking.

Responsibilities

• Perform network incident detection and response to identify threats.
• Monitor security tools and investigate alerts; recommend mitigations.
• Document events with technical writing in a ticketing system.

Skills

Windows

Red Hat

Networking

Education

Bachelor's degree

Tools

Splunk

Elastic

Job description

Primary Responsibilities

• Perform computer network incident detection and response activities to detect, correlate, identify, and characterize anomalous activity indicative of threats to the CESO enterprise.
• Monitor security tools and applications for possible malicious activity, investigate associated alerts or indicators, and develop recommendations for a course of action, including mitigation strategies as required.
• Document each event and its associated analysis in a ticketing system with clear, accurate technical writing so it can be reviewed and acted on appropriately.
• Maintain regular face-to-face interaction with the customer; handle issues when they are raised by the customer with little or no supervision.
• Positively influence team performance by improving CESO processes and procedures.
• Ensure system checks are performed in a timely manner and that documentation is complete and accurate.
• Assist senior analysts and/or managers with forecasting and modeling current threats.
• Develop a strong rapport with the customer and serve as a trustworthy network defense analyst.
• Collaborate with infrastructure, storage, database, and application teams to align network defense monitoring with CESO's operational requirements as the program transitions to its secure cloud environment.

Basic Qualifications

• Bachelor's degree and 2+ years of related experience; additional experience, education, or training may be considered in lieu of degree.
• Active TS/SCI security clearance required for this position.
• DoDD 8140 IAT Level II (or Level III) certification (e.g., Security+ CE).
• Strong computing systems knowledge with Windows, Red Hat, Cloud (AWS, Azure), and particularly networking, including communication protocols and familiarity with common security elements such as IDS/IPS systems and firewalls.
• Experience with implementing application/hardware security settings using vendor and DISA best business practices.
• Candidate may be asked to obtain a CI Polygraph in the future.

Preferred Qualifications

• Prior CND experience, ideally within a large enterprise or DoD/IC program environment.
• Experience monitoring intrusion detection and computer network defense appliances, applications, and analyzing associated alerts.
• Experience documenting analysis and providing response recommendations in a ticketing/case management system.
• Experience reviewing system logs manually and using automatic SIEMs tools (e.g., SPLUNK, Elastic) and performing network log analysis.
• Prior experience with DISA and DISA's support to mission partners.
• An Understanding of disaster recovery and business continuity concepts as they apply to secure cloud migrations.

This position is based in Arlington, VA and is 100% on-site.

Requires a TS/SCI US Government Security Clearance to start.

Pay Range: $69,550.00 - $125,725.00

The Leidos pay range for this job level is a general guideline only and not a guarantee of compensation or salary. Additional factors considered in extending an offer include (but are not limited to) responsibilities of the job, education, experience, knowledge, skills, and abilities, as well as internal equity, alignment with market data, applicable bargaining agreement (if any), or other law.

Original Posting

September 22, 2026

For U.S. Positions: While subject to change based on business needs, Leidos reasonably anticipates that this job requisition will remain open for at least 3 days with an anticipated close date of no earlier than 3 days after the original posting date as listed above.