Systeembeheerder (m/w/d )

We are looking for an experienced System Administrator, OT Platforms for a temporary assignment.
The client currently needs additional support to make progress on technical debt and strengthen the technical foundation of its OT environment. The focus is on implementing ISMS measures, cleaning up Active Directory for IAM, rolling out security policies and optimizing patching across critical infrastructure.
This is a temporary support assignment, intended to accelerate ongoing improvements rather than fill a permanent position.
As a System Administrator within OT Platforms, you will work on the digital infrastructure supporting the energy network. You will contribute directly to a stable, secure and future-proof OT environment that is essential to the reliability of the organization's services.
What will you do?
As part of the OT Platforms team, you will independently take ownership of technical improvements and work closely with colleagues to further strengthen the quality, security and manageability of the environment.
Your responsibilities will include:
Cleaning up, standardizing and optimizing Active Directory.
Implementing ISMS measures and security improvements.
Addressing and following up on audit findings.
Processing and resolving findings resulting from penetration tests.
Setting up and improving monitoring for the OT domain to support the Cyber Defense Center (CDC).
Improving system administration processes and system configurations.
Optimizing patch management across critical infrastructure.
Implementing and enforcing security policies.
Automating recurring administrative tasks.
Working closely with platform engineers, architects, security specialists and system administrators.
A typical day:
You start the day with a short team alignment, followed by an analysis of audit findings and translating them into concrete improvement actions across Windows and Linux environments.
Later in the day, you may work on cleaning up Active Directory by rationalizing outdated groups, accounts and permission structures. Together with security colleagues, you determine which measures are required to make the environment more secure and manageable.
On another day, you may configure monitoring for new OT platforms so that relevant events can be identified in a timely manner by the Cyber Defense Center. You may also investigate opportunities to further automate administrative tasks using Ansible.
No two days are the same, but the common goal remains clear: increasing the security, stability and manageability of the OT infrastructure.
Your working environment:
You will join the OT Platforms team within a technical organization focused on IT and OT infrastructure, security, operations and services.
The team consists of specialists in platforms, infrastructure, security, system administration and service delivery. Together, they manage a business-critical OT environment that plays an important role in supporting the energy network.
You will work in an open and collaborative environment where knowledge sharing, teamwork and ownership are highly valued.
We are looking for a pragmatic and experienced System Administrator who can work independently and turn technical improvements into concrete results. You are comfortable working in complex infrastructure environments and have a strong interest in security and automation.
You have:
A completed Bachelor's degree (HBO level) in a relevant technical field.
Demonstrable experience with Active Directory and IAM principles.
Demonstrable experience with Linux and Windows system administration.
Knowledge of Identity & Access Management, hardening and security measures.
Experience handling and following up on audit and security findings.
Experience with monitoring solutions and log management.
Experience with Ansible is a strong plus.
Experience in an OT, industrial or critical infrastructure environment is a plus.
A practical, hands-on approach and the ability to work independently.

Employment type
Full-time

Work arrangement
No