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Jonathan ChambreJC

Jonathan Chambre

Pentester | Penetration Testing Expert

€550/day
Paris, FR
8-15 years

Average response time: 12 hours

Freelancer profile translated to English.
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About Jonathan

Penetration Testing Expert (Pentest) - 8+ years of experience

For over 8 years, I have been assisting startups, SMEs, and large corporations in assessing, preventing, and remediating cyber risks.

My role: to act as an ethical hacker to identify your security vulnerabilities before an attacker exploits them.

🔐 My main areas of expertise:
  • Penetration Testing (Pentest): web and mobile applications, internal networks, cloud, Active Directory, Wi-Fi, phishing, Red Team, AI & LLM
  • Security Audits : configuration, architecture, and organization
💼 My approach:
  • Understanding your business challenges
  • In-depth technical testing adapted to your context
  • Clear report with concrete and prioritized recommendations
  • Educational debrief (technical version + managerial version)
  • Support until the implementation of fixes
Published Vulnerabilities:
CVE-2025-67082, CVE-2025-67083, CVE-2025-67084, CVE-2025-67076, CVE-2025-67077, CVE-2025-67078, CVE-2025-67079, CVE-2025-67081
  • French

    Native or bilingual

  • English

    Fluent

Can work on-site
Paris (up to 50km)

Experience

  • HELX
    Founder
    CONSULTING AND AUDITS
    March 2025 - Today (1 year and 3 months)
    Paris, France
    HELX (is a cybersecurity expertise company created by passionate consultants, with a clear mission: to make IT security more accessible, understandable, and effective.

    Our expertise to meet specific and precise needs.
    • Penetration tests / pentest (web, infra, mobile, API, ...)
    • Technical & strategic audits
    • Training & awareness
    • Security hardening & post-audit support
    • Incident response & forensics
    Cybersecurity Penetration Testing PenTest web penetration testing Pentester
  • Lexfo
    Pentester
    CONSULTING AND AUDITS
    September 2023 - February 2025 (1 year and 5 months)
    Paris, France
    Senior cybersecurity consultant within the Pentest team, involved in conducting various security audits: web, network, internal, API, and cloud penetration tests.

    Assisting clients in evaluating and strengthening the security of their information systems by simulating realistic attack scenarios.

    Key responsibilities:
    • Pentest & audits: conducting penetration tests on various systems (Web, network, internal, API, cloud), Red Team exercises
    Internal Penetration Testing Web Pentest Red Team web penetration testing Pentester
  • COGICEO
    IT Security Consultant
    CONSULTING AND AUDITS
    February 2017 - September 2023 (6 years and 7 months)
    Paris, France
    6 years of experience at Cogiceo allowed me to assist clients from various sectors (industry, logistics, banking, energy) in securing their systems through:
    • penetration tests (pentests),
    • in-depth technical audits,
    • and targeted Red Team missions.
    Key responsibilities:
    • Pentest & audits: conducting penetration tests on various systems (Web, network, internal, API, cloud)
    • Project management: receiving client requirements, defining mission scope, and operational monitoring until deliverable presentation
    • Team leadership: operational management of a team of 4 pentesters
    Active Directory Red Team Internal Penetration Testing web penetration testing

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Education

  • Engineering Degree, Computer Science
    ENSEIRB-MATMECA
    2017
    Diplôme d'ingénieur, Informatique

Certifications

  • OSCP
    Offensive Security
    2017
  • CHFI
    E-Council
    2020

Skill set

Categories