Computer Network Defense Analyst

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

Job summary

Leidos is seeking a Cyber Network Defense Analyst to join the CESO effort in Arlington, VA. The role is 100% on-site and requires a TS/SCI clearance to start. You will detect incidents, monitor security tools, document analyses, and coordinate with cross-functional teams to defend CESO’s secure cloud migration.

The position emphasizes collaboration with infrastructure, storage, database, and application teams, and includes interaction with the customer to ensure timely and accurate responses.

Qualifications

• Bachelor’s degree with 2+ years of related experience; additional experience may be considered in lieu of degree.
• Active TS/SCI clearance required to start.
• DoDD 8140 IAT Level II certification (e.g., Security+ CE).
• Strong knowledge of Windows, Linux, cloud (AWS/Azure), and networking; familiarity with IDS/IPS and firewalls.
• Experience implementing security settings per vendor and DISA best practices.
• Candidate may be asked to obtain a CI Polygraph in the future.

Responsibilities

• Detect, correlate, and characterize anomalous activity indicating threats to CESO enterprise.
• Monitor security tools for malicious activity; investigate alerts and recommend actions.
• Document events and analyses with clear technical writing in the ticketing system.
• Maintain regular face-to-face interaction with the customer; respond to issues with minimal supervision.
• Improve CESO processes and procedures to influence team performance.
• Ensure timely system checks and complete documentation.
• Assist senior analysts/managers with forecasting and modeling current threats.
• Develop rapport with the customer and serve as a trusted CESO network defense analyst.
• Collaborate with infrastructure, storage, database, and application teams during secure cloud migration.

Skills

Windows OS

Red Hat Linux

AWS

Azure

Networking basics

IDS/IPS

Firewalls

SIEM (Splunk, Elastic)

Security best practices

Education

Bachelor’s degree

DoDD 8140 IAT Level II certification

Tools

SPLUNK

Elastic

Ticketing system

Job description

We are currently seeking a Cyber Network Defense Analyst to join the Compartmented Enterprise Services Office (CESO) effort. This program is establishing a modern secure web service (SWS) operation as part of a state-of-the-art, highly automated platform capable of supporting a rapidly expanding customer population. Our team supports CESO’s mission to protect networked systems and services from cyber threats as CESO migrates to a high security cloud environment, operating as a 24x7, mission-critical function providing network defense, monitoring, and incident response services. We are looking for a self-starter capable of independently performing daily tasks while also working well within a team that requires significant coordination and communication.

This position is based in Arlington, VA and is 100% on-site.
Requires a TS/SCI US Government Security Clearance to start.

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.

#ceso

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.

Pay Range:

Pay Range $69,550.00 - $125,725.00

The Leidos pay range for this job level is a general guideline onlyand 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.