Security Operations Center Group Manager (L3) -Cyber Defense Operations Section (RMI Telecommunication Security Supervisory Dep)
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Before you apply
LocationTokyo, Japan; Osaka, Japan
Typefull-time
SeniorityLead
Experience10+ yrs
Company size10,000+ people
PostedSep 23, 2026 · 1mo ago
Verified live4d ago
At a glanceSummarised by Seekless from the posting.
Proven experience leading technical teams in a 24/7 environment
Deep understanding of leveraging AI for threat hunting, anomaly detection, and automated response
Strong experience in a Telco environment, including knowledge of SS7/Diameter/GTP protocols, 5G core security, and virtualization
Expert-level knowledge of containerization (Docker) and Kubernetes (K8s) security
Advanced scripting skills (Python, Go, or Bash) and extensive experience with SOAR platforms
Expert capability in conducting digital forensics and managing incident response lifecycles
10+ years in Cyber Security
At least 6 years in a leadership role within a SOC
Bachelor's or Master's degree in Computer Science, Cyber Security, or a related field
Relevant industry certifications (e.g., CISSP, CISM, GCIH, GCFA, or equivalent)
Experience with LLM-based security tools or AI-vs-AI defense strategies
Experience in high-traffic, low-latency environments typical of modern Telecommunications
Active participation in the security community (e.g., public speaking, research papers, or open-source security tool development)
Experience with cloud security (AWS/Azure/GCP) in a hybrid-Telco environment
Skills
Python
Go
Bash
Docker
Kubernetes
SOAR
AWS
Azure
GCP
LLM
Job Description:
About Organization
Cyber Defense Operations Section operates a 24/7 Security Operations Center (SOC) protecting Rakuten Group’s critical infrastructure. We are currently in a critical transformation phase to address the era of autonomous, AI-driven cyber threats. Our goal is to evolve from a reactive monitoring unit into a proactive, intelligence-led, and autonomous defense organization. We are seeking a visionary and hands-on SOC Lead to architect our future-ready security operations, leveraging AI and automation to neutralize machine-speed attacks while mentoring high-performing security talent.
Job Duties
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Strategic Transformation: Lead the evolution of the SOC from a reactive monitoring unit to an autonomous, AI-augmented defense organization.
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AI & Automation Engineering: Architect and implement AI-driven detection and response workflows. Drive the integration of SOAR (Security Orchestration, Automation, and Response) to counter autonomous AI attacks.
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Operational Leadership: Manage the 24/7 SOC team, ensuring high-availability monitoring, rapid incident response, and continuous service improvement.
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Technical Oversight: Provide L3-level escalation support for complex incidents. Oversee security monitoring of Telco-specific network architectures, containerized environments, and Kubernetes (K8s) clusters.
•
Governance & Documentation: Establish rigorous SOC governance, including the creation and maintenance of playbooks and SOPs that meet international audit and compliance standards.
•
DFIR & Root Cause Analysis: Assist in high-stakes Digital Forensics and Incident Response (DFIR) efforts, conducting deep-dive analysis to harden the environment against future threats.
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Stakeholder Collaboration: Partner with cross-functional security teams and Business Units to ensure security is integrated throughout the infrastructure lifecycle.
•
Innovation & Research: Stay at the bleeding edge of offensive and defensive AI research to proactively adapt security posture against evolving adversary tactics.
Minimum Qualifications
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Leadership: Proven experience leading technical teams in a 24/7 environment; demonstrated ability to mentor and grow security talent.
•
AI/ML in Security: Deep understanding of leveraging AI for threat hunting, anomaly detection, and automated response.
•
Telco & Infrastructure: Strong experience in a Telco environment, including knowledge of SS7/Diameter/GTP protocols, 5G core security, and virtualization.
•
Cloud-Native Security: Expert-level knowledge of containerization (Docker) and Kubernetes (K8s) security.
•
Automation: Advanced scripting skills (Python, Go, or Bash) and extensive experience with SOAR platforms.
•
DFIR: Expert capability in conducting digital forensics and managing incident response lifecycles.
•
Experience: 10+ years in Cyber Security, with at least 6 years in a leadership role within a SOC.
•
Education: Bachelor’s or Master’s degree in Computer Science, Cyber Security, or a related field.
•
Certifications: Relevant industry certifications (e.g., CISSP, CISM, GCIH, GCFA, or equivalent).
Preferred Qualifications
•
Experience with LLM-based security tools or “AI-vs-AI” defense strategies.
•
Experience in high-traffic, low-latency environments typical of modern Telecommunications.
•
Active participation in the security community (e.g., public speaking, research papers, or open-source security tool development).
•
Experience with cloud security (AWS/Azure/GCP) in a hybrid-Telco environment.
Work Environment
•
Reporting: Reports to the Head of Cyber Defense Operations Section.
•
Collaboration: Manages the 24/7 SOC team and collaborates cross-departmentally with other security functions and Business Units.
•
Tech Stack: Containerization (Docker/K8s), Telco environment (5G Core, Signaling Protocols), SOAR platforms, Python/Go/Bash, Cloud Security (AWS/Azure/GCP), and LLM-based security tools.
Languages:
English (Overall - 3 - Advanced)
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