Senior Penetration Tester, Security Operations Center Group Cyber Defense Operations Section (RMI Security Eng. & Ops Dep)

Tokyo - Japan

Monthly Salary: Not Disclosed

Posted on: 17 hours ago

Vacancies: 1 Vacancy

Job Summary

Job Description:

About Organization

Rakuten Mobile Inc. is an entity established for the launch of its mobile carrier business as an MNO (Mobile Network Operator.) We aim to provide the most competitive and convenient service to meet our customer needs and demands via the innovative use of technology. Defining future world-standard innovations in the MNO industry we continually challenge ourselves and capabilities. We are looking for talented individuals who are interested in working with us to create and deliver world class solutions.

We are looking for a seasoned Senior Penetration Tester with 1012 years of hands-on experience in offensive security. This role covers advanced penetration testing red teaming and AI security testing. Based in Tokyo you will work closely with global and Japan-based engineering product and security teams.

Job Duties

Roles & Responsibilities:

Penetration Testing & Red Teaming (Traditional AI):

Lead complex penetration tests across web mobile API internal infrastructure and cloud environments.
Execute red team engagements simulating sophisticated threat actors.
Perform high-level AI/ML security assessments including testing LLM-integrated systems.
Identify and exploit vulnerabilities and develop proof-of-concepts.
Review system and application architectures to identify security gaps.
Produce technical reports and present findings to engineering and leadership teams.
Contribute to improving internal offensive security methodologies including those related to AI-enabled platforms.

Minimum Qualifications

1012 years of hands-on penetration testing red teaming or offensive security experience.
Strong expertise in web mobile API network and infrastructure security.
Solid experience with cloud environments (AWS Azure GCP).
Understanding of OWASP PTES MITRE ATT&CK and modern adversarial techniques.
Proficiency with tools such as Burp Suite Pro Nmap Metasploit Cobalt Strike BloodHound Kali Linux.
Strong scripting skills (Python Bash PowerShell).
Familiarity with AI/ML concepts and LLM-based applications.
Soft Skills
- Excellent analytical and problem-solving skills.
- Strong written and verbal communication abilities.
- Ability to work independently and lead offensive security initiatives.
- High integrity and responsibility in security testing.

Preferred Qualifications

OSCP OSWE OSEP OSCE3
GIAC GPEN GWAPT GXPN
CREST CRT / CCT
Cloud security certifications (AWS / Azure / GCP)
Experience or research in AI/ML security is a plus
Japanese Language : Ideal to have (Business or Technical proficiency preferred)

Languages:

English (Overall - 3 - Advanced)

Required Experience:

Senior IC

Job Description:About OrganizationRakuten Mobile Inc. is an entity established for the launch of its mobile carrier business as an MNO (Mobile Network Operator.) We aim to provide the most competitive and convenient service to meet our customer needs and demands via the innovative use of technology....