Senior Manager – Cybersecurity Operations

Castelion Corporation; Torrance (CA); On-site; USD 180,000 - 240,000; Full time

Job summary

Castelion is seeking a Senior Manager – Cybersecurity Operations to lead defensive security operations, incident response, and threat monitoring for our defense-focused systems in Torrance, CA.

You will own SOC activities, drive threat hunting, and design defense-in-depth strategies aligned with NIST and DoD; oversee SIEM/EDR deployments and coordinate with engineering and IT to keep critical infrastructure secure.

Qualifications

• 7+ years of hands-on cybersecurity experience with a focus on defensive operations
• 2+ years in a leadership or team lead capacity
• Proven experience in defense, aerospace, engineering, intelligence, government, or critical infrastructure sectors
• Experience in regulated environments (DoD, CMMC, NIST 800-171, ISO 27001, etc.)
• Demonstrated expertise in security monitoring, threat hunting, and incident response
• Understanding of APT tactics and techniques
• Hands-on experience with enterprise security tools (SIEM, EDR, IDS/IPS, firewalls, proxies)
• Expert knowledge of network protocols, security architecture, and system hardening
• SIEM platform proficiency (configuring and consuming)
• Strong Windows and Linux security and forensics knowledge
• EDR solutions experience (CrowdStrike, Carbon Black, Defender, SentinelOne)
• Scripting and automation (Python, PowerShell, Bash)
• Cloud security knowledge (AWS, Azure, GovCloud)
• Malware analysis, reverse engineering, and penetration testing understanding
• Threat intelligence platforms and indicator management experience
• Security principles and frameworks knowledge (MITRE ATT&CK, NIST, CIS Controls)
• Strong documentation, troubleshooting, and communication skills
• Ability to thrive under pressure with competing priorities
• Analytical mindset and ongoing threat landscape awareness

Responsibilities

• Contribute to and mature our SOC activities ensuring effective threat detection and response
• Direct threat hunting operations to proactively neutralize threats
• Lead incident response for security events affecting all information systems
• Develop and maintain defensive playbooks, runbooks, and SOPs
• Coordinate with internal teams to validate defensive posture
• Design defense-in-depth strategies aligned with NIST, DoD, and relevant frameworks
• Evaluate and deploy advanced security technologies (SIEM, EDR/XDR, SOAR)
• Create and maintain security architecture documentation and network defense diagrams
• Contribute to security roadmap planning
• Establish threat intelligence program aligned to aerospace and defense threats
• Analyze TTPs using MITRE ATT&CK framework
• Produce threat intelligence reports for technical and executive audiences
• Collaborate with government agencies and industry partners on threat information sharing
• Track emerging threats and vulnerabilities relevant to defense systems
• Contribute to compliance (NIST 800-171, CMMC, ITAR, DFARS)
• Support security audits, assessments, and penetration testing
• Partner with IT ops, engineering, and program management on security initiatives
• Coordinate with government customers on security matters
• Serve as SME for changes to cyber controls and policies

Skills

Threat hunting

Incident response

Security operations

Documentation

Communication

Problem solving

Education

Active Security+, CISSP, GIAC, GCIA, GCIH, GCFA, CISA, CEH (certifications)

U.S. security clearance eligibility

Tools

SIEM

EDR/XDR

CrowdStrike

Carbon Black

Defender

SentinelOne

IDS/IPS

Firewalls

Job description

Why Castelion, Why Now

Castelion is moving incredibly fast to develop and deliver advanced defense systems at a time when execution matters more than ever. We believe focus, ownership, and excellence are decisive advantages - and we’re building a world-class team to turn bold ideas into real capability.

This is a rare opportunity to join at an early stage, where you’ll have significant ownership, collaborate with exceptional teammates, and make a direct, measurable impact on our mission and the future of the company - regardless of your function.

Senior Manager – Cybersecurity Operations

We are seeking an experienced Senior Manager – Cybersecurity Operations to join our cybersecurity operations team at Castelion. This critical role will lead defensive security operations, incident response, and threat monitoring, protecting our information systems, intellectual property, product development security, and critical infrastructure from common threat vectors as well as advanced persistent threats (APTs) and nation‑state actors.

The ideal candidate will envision security to remain a business enabler and not a blocker, have deep expertise in defensive security operations, SOC leadership, proactive threat hunting, SIEM & SOAR, and incident response within highly regulated environments. Brings a practical, and up-to-date relevant technical understanding of protocols, encryption levels, patch levels, policy & procedure, etc., that are secure in the modern cybersecurity landscape.

Responsibilities:

• Contribute to and mature our Security Operations Center (SOC) activities and ensure effective threat detection and response
• Direct threat hunting operations to proactively identify and neutralize threats before impact
• Lead incident response efforts for security events affecting all our information systems
• Develop and maintain defensive playbooks, runbooks, and standard operating procedures
• Coordinate with additional internal teams to conduct exercises that validate defensive posture
• Design and implement defense-in-depth strategies aligned with NIST, DoD, and intelligence community frameworks
• Evaluate and deploy advanced security technologies (SIEM, EDR/XDR, SOAR, threat intelligence platforms)
• Create and maintain security architecture documentation and network defense diagrams
• Contribute to security roadmap planning
• Establish and maintain threat intelligence program aligned to aerospace and defense sector threats
• Analyze threat actor tactics, techniques, and procedures (TTPs) using MITRE ATT&CK framework
• Produce threat intelligence reports and briefings for technical and executive audiences
• Collaborate with government agencies and industry partners on threat information sharing
• Track emerging threats and vulnerabilities relevant to defense systems and aerospace technology
• Contribute to compliance with NIST 800-171, CMMC, ITAR, DFARS, and other applicable regulations
• Support security audits, assessments, accreditation activities, and regular penetration testing
• Partner with IT operations, engineering, and program management teams on security initiatives
• Coordinate with government customers and oversight bodies on security matters
• Function as a primary stakeholder and subject matter expert for changes to cyber controls and policies

Required Qualifications:

• 7+ years of hands‑on experience in cybersecurity, with a focus in defensive operations
• 2+ years in a leadership or team lead capacity
• Proven experience operating in defense, aerospace, engineering, intelligence, government, or critical infrastructure sectors
• Experience in regulated environments (DoD, CMMC, NIST 800‑171, ISO 27001, etc.)
• Demonstrated expertise in security monitoring, threat hunting, and incident response
• Demonstrated understanding of advanced persistent threat (APT) tactics and techniques
• Hands‑on experience with enterprise security tools (SIEM, EDR, IDS/IPS, firewalls, proxies)
• Expert knowledge of network protocols, security architecture, and system hardening
• Expert proficiency as both a configurator and a consumer of security information and event management (SIEM) platforms
• Strong understanding of Windows and Linux security and forensics
• Experience with endpoint detection and response (EDR) solutions (CrowdStrike, Carbon Black, Defender, SentinelOne, etc.)
• Proficiency with scripting and automation (Python, PowerShell, Bash)
• Knowledge of cloud security (AWS, Azure, GovCloud)
• Understanding of malware analysis, reverse engineering techniques, and penetration testing
• Experience with threat intelligence platforms and indicator management
• Deep understanding of security principles, threats, and frameworks (e.g., cyber kill chain, MITRE ATT&CK, NIST, CIS Controls).
• Strong documentation, troubleshooting, and communication skills.
• Ability to thrive in fast‑paced, high‑pressure environments with competing priorities.
• Analytical mindset with strong problem‑solving abilities
• Commitment to staying current with evolving threat landscape

Preferred Qualifications:

• Active Security+, CISSP, GIAC, GSOC, GCIA, GCIH, GCFA, CISA, CEH, or similar senior‑level certifications
• Eligibility to keep and maintain a U.S. security clearance.

What We’re Looking For:

• A proactive security professional who sees audits and compliance as opportunities to build better systems – not just check boxes.
• A disciplined thinker who can balance security, business needs, and regulatory constraints.
• A calm, solutions‑oriented team member who leads by example during assessments, incidents, or high‑pressure reviews.
• A clear communicator who knows how to educate non‑technical stakeholders without watering things down.

Castelion offers a generous benefits package. Please refer to the bottom of our Careers page for more details.

Other Duties

Please note this job description is not designed to cover or contain a comprehensive listing of activities, duties or responsibilities that are required of the employee for this job. Duties, responsibilities and activities may change at any time with or without notice.

Additional Eligibility Requirements

This position may require access to classified information or restricted U.S. Government sites, systems, or information, as determined by the Company and/or applicable U.S. Government requirements. If the position is so designated, your employment in the role may be contingent upon your ability to obtain and maintain the required U.S. Government security clearance or other government authorization, and to satisfy any citizenship or other eligibility requirements imposed by applicable law, regulation, executive order, or government contract requirements. You will be notified if and when such requirements apply.

Affirmative Action/EEO Statement

Castelion is an Equal Opportunity Employer. We are committed to providing equal employment opportunities to all applicants and employees without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability, genetic information, protected veteran status, or any other characteristic protected by applicable federal, state, or local law.

Castelion is committed to providing reasonable accommodations to qualified individuals with disabilities throughout the application and hiring process. If you require a reasonable accommodation to complete an application, participate in the interview process, or otherwise participate in the hiring process, please contact [e-mail]. Requests for accommodation will be considered on an individual basis and handled in accordance with applicable law.

Castelion is committed to fostering a workplace where employment decisions are based on qualifications, business needs, and the ability to perform the essential functions of the role, with or without reasonable accommodation.

EAR/ITAR Requirements

This position requires access to export‑controlled information, and as such, employment (or hiring of a contractor) is contingent upon the candidate’s ability to access all applicable export‑controlled information without additional export licensing being required by the Bureau of Industry and Security and/or the Directorate of Defense Trade Controls.