Cybersecurity Engineer (Freelance) – 12 months – Brussels
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About the Role
Our client is embarking on a major transformation to modernize and secure their infrastructure through a DevSecOps approach. As a Cybersecurity Engineer, you will be at the heart of this mission, driving the integration of security, compliance, and automation across complex, heterogeneous environments. Your work will directly impact the resilience and future-readiness of critical systems in a high-stakes, high-availability setting.
This is a freelance position for 12 months, based in Brussels.
Why This Role Matters
Security is not just a requirement — it's a foundation. You will help solve the business-critical challenge of protecting vital infrastructure, ensuring compliance with leading frameworks, and enabling secure, rapid innovation. Your expertise will close the gap between legacy constraints and modern security standards, directly influencing operational stability and regulatory readiness.
Key Responsibilities
* Implement, manage, and secure patch management, hardening, and compliance systems across physical and virtual servers
* Drive OS hardening (CIS, ANSSI, vendor guidelines) for Windows and Linux environments
* Configure host firewalls, local security rules, and implement disk/volume encryption
* Design and maintain secure, automated VM onboarding processes
* Automate patching cycles using secure pipelines and templates
* Deploy and maintain system software (Windows & Linux), ensuring rapid response to urgent security updates
* Generate activity and compliance reports, supporting audit and regulatory requirements
* Manage patching across diverse environments, including legacy systems and virtualization platforms (VMware, Citrix/Xen, Kubernetes)
* Ensure system stability post-patching and support CAB/change management processes
* Maintain comprehensive documentation: SOPs, procedures, audit evidence
* Set up test and validation environments for secure deployment
* Resolve backlog of unpatched servers and apply compensatory security measures where needed
* Implement rollback and remediation mechanisms for patching failures
* Support vulnerability prioritization and define security baselines for Windows and Linux
* Collaborate closely with infrastructure, development, and security teams to drive a unified security vision
Technical Skills & Tools
* Expertise in patch management systems (WSUS, SCCM, third-party tools)
* Strong hands-on experience with orchestration and configuration tools (Ansible, PowerShell, Bash)
* Advanced knowledge of Windows Server and Linux administration
* Experience with virtualization: VMware, Citrix/Xen, Docker, Kubernetes
* Mastery of security baselines, STIGs, GPO, SCAP, CIS standards
* Solid understanding of cloud environments (IaaS/PaaS) and on-premise datacenter operations
* Proven ability to automate patching and hardening processes
* Experience with vulnerability management methodologies; Qualys expertise is a plus
* Comfortable managing technical debt, upgrades, and standardization in complex environments
Language Proficiency
* English: Full professional proficiency
* French: Full professional proficiency
Other Requirements
* Minimum 5 years of relevant experience with a university degree, or 10 years proven experience without a degree
* Experience across the full IT systems lifecycle, including high-pressure, critical security situations
* Ability to design processes from scratch and document them clearly
* Strong organization, prioritization, and analytical skills
* Experience in high-availability environments and direct interaction with business stakeholders
* Familiarity with reference frameworks: CyFun2025, NIS2, ENISA ECSF, ISO/IEC 27001/27002, NIST CSF 2.0 (PROTECT, DETECT, RESPOND)
Working Conditions
* Full-time, on-site in Brussels
Role & Experience Level
* Role: Medior IT Security Engineer
* Experience: Open to all levels meeting the above requirements
Technical Validation Topics
* Citrix XenServer Virtualization – Advanced
* Windows Server Hardening – Advanced
* Linux Server Hardening – Advanced
* Automating Patching Cycles – Advanced
* Vulnerability Management Methodology – Advanced
* Qualys expertise – Nice to have
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