Senior Cybersecurity Analyst — Threat Detection & Incident Response

Castelion Corporation; Torrance (CA); Hybrid; USD 120,000 - 150,000; Full time

Job summary

Castelion is seeking a Senior Cybersecurity Analyst to protect critical national security systems and data. You will lead 24/7 security monitoring, perform threat analysis, and drive incident response across hybrid environments in a defense-focused setting.

Qualified candidates will have hands-on security operations experience, MITRE ATT&CK expertise, and the ability to obtain/maintain a U.S. security clearance.

Qualifications

• 3+ years of experience in cybersecurity, information security, or related technical security roles.
• Hands-on experience with security operations, incident response, and threat analysis.
• Expert knowledge of security tools: SIEM (Splunk, QRadar, Sentinel), EDR (CrowdStrike, Carbon Black), IDS/IPS.
• Deep knowledge of MITRE ATT&CK framework and adversary tactics, techniques, and procedures.
• Familiarity with threat intelligence platforms and OSINT techniques.
• Experience protecting Controlled Unclassified Information (CUI).
• Experience operating within aerospace, defense, national security, government contracting, or highly regulated technical environments.
• Strong understanding of network protocols, operating systems (Windows, Linux), and cloud environments.
• Experience as a member of incident response protocols, vulnerability management, and security operations functions.
• Proficiency in scripting/automation.
• U.S. Person status required to comply with ITAR regulations.
• Ability to obtain and maintain a U.S. security clearance.

Responsibilities

• Lead 24/7 security monitoring efforts using SIEM platforms and advanced threat detection tools.
• Analyze security events, identify potential threats, and coordinate incident response activities.
• Identify vulnerabilities and recommend remediation strategies for complex environments.
• Analyze malware, APT tactics, and threat actor behavior.
• Perform threat hunting activities to proactively identify sophisticated adversaries.
• Conduct forensic analysis of security incidents involving classified and sensitive systems.
• Contribute to compliance with NIST 800-171, CMMC, DFARS, ITAR, and other DoD requirements.
• Contribute to and/or maintain security documentation including internal documentation, policies and procedures, incident reports, and audit artifacts.
• Configure and maintain security tools including IDS/IPS, EDR, DLP, and vulnerability scanners.
• Support secure architecture reviews across the organization.
• Mentor junior analysts and contribute to team skill development.
• Coordinate with IT, engineering, manufacturing, and program teams on security initiatives.
• Participate in threat intelligence sharing with government and industry partners.

Job description

Castelion is seeking a Senior Cybersecurity Analyst to protect critical national security systems and data. You will lead 24/7 security monitoring, perform threat analysis, and drive incident response across hybrid environments in a defense-focused setting.

Qualified candidates will have hands-on security operations experience, MITRE ATT&CK expertise, and the ability to obtain/maintain a U.S. security clearance.