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Harold MertzweillerHM

Harold Mertzweiller

ICS and OT Security Expert | DevSecOps | OSCP

€1,200/day
Zurich, CH
8-15 years

Average response time: 1 hour

About Harold

I am a security engineer with a strong foundation in embedded systems, Linux, and cloud infrastructure. I currently work at Google in Zurich, where I focus on audits of third-party products, security reviews and consulting. I work with ISO 27001, NIST SP 800-82 and IEC 62443 standards.



Prior to this, I held engineering roles across embedded development and DevOps. At Elsys Design, I developed Linux-based communication software and contributed to bootloader and kernel-level modifications for custom platforms. At Edenred, I supported critical infrastructure through system administration, led cloud migration efforts, and implemented Infrastructure as Code using Ansible.

With a Master’s degree in Cybersecurity and a background in mathematics and systems programming, I bring a pragmatic approach to securing both hardware and software systems across the stack.I am a security engineer with a strong foundation in embedded systems, Linux, and cloud infrastructure. I currently work at Google in Zurich, where I focus on product security reviews, asset inventory systems, and audits of third-party products. Prior to this, I held engineering roles across embedded development and DevOps. At Elsys Design, I developed Linux-based communication software and contributed to bootloader and kernel-level modifications for custom platforms. At Edenred, I supported critical infrastructure through system administration, led cloud migration efforts, and implemented Infrastructure as Code using Ansible. With a Master’s degree in Cybersecurity and a background in mathematics and systems programming, I bring a pragmatic approach to securing both hardware and software systems across the stack.
  • French

    Native or bilingual

  • English

    Fluent

  • German

    Basic

Remote only
Primarily works remotely

Experience

  • Google Switzerland GmbH
    Security Engineer
    June 2022 - Today (4 years)
    Zurich, Switzerland
    • Product Security Reviews: Participated in security reviews and threat modeling for new products and features.
    • Asset Inventory Management: Contributed to the development and maintenance of an internal asset inventory system to track critical infrastructure.
    • External Product Audits: Conducted security audits of external products (OT devices, security appliances), including responsible disclosure of vulnerabilities (e.g., CVE-2024-57811).
    • Cloud IAM Hardening: Involved in the development of internal tools for threat detection and incident response automation, with a focus on Cloud IAM configurations.
    ICS Cybersecurity ISO 27001 IEC 62443 Cybersécurité
  • Elsys Design
    Embedded Software Engineer
    November 2019 - January 2021 (1 year and 2 months)
    Grenoble, France
    • Linux Embedded Development: Developed and maintained train-side communication software (GSM-R protocol) in C and C++ on Linux embedded devices for Alstom, ensuring reliable data transmission for critical systems.
    • Kernel and Bootloader Development: Modified U-Boot bootloader and Linux kernel by creating and applying patches for custom hardware platforms for Schneider Electric.
    C++ Linux Systèmes embarqués
  • Edenred
    Linux System Administrator and DevOps
    TECH
    October 2018 - November 2019 (1 year and 1 month)
    Grenoble, France
    • System Administration: Managed on-premise Linux servers and infrastructure; responded to security incidents and ensured availability and reliability of critical services.
    • Cloud Migration & SysOps: Led the migration of on-premise infrastructure to the cloud (AWS), and implemented Infrastructure as Code (IaC) using Ansible for automated build and deployment processes.

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Education

  • Licence de Mathématiques
    Université de Lorraine
    2016
  • Master Cybersécurité
    Université Grenoble Alpes
    2018

Certifications

Skill set

Categories