Dylan Poelstra

Offensieve beveiligingsconsultant met praktische ervaring in het leiden van volledige enetratietests, phishing-simulaties en beveiligingsadviesprojecten in diverse bedrijfsomgevingen.

Ervaringen op het gebied van het verbeteren van beveiligingsprocessen, het geven van advies over architectuur en het werken binnen zowel red- als blue-team-domeinen. Sterke achtergrond in infrastructuur, cloud (Azure) en beveiligingsmaatregelen voor ondernemingen (PAM, WAF, MDR).

Penetration Tester | Consultant

Grant Thornton Netherlands - Full time

Sep 2024 - Present

Lead end-to-end penetration testing engagements (scoping → execution → reporting → client delivery) across web, infrastructure, and cloud environments

• Executed and scaled Phishing-as-a-Service offering, including campaign design, execution, reporting, and client advisory
• Acted as Technical Information Security Officer within CISO-as-a-Service engagements, advising on security posture and risk mitigation
• Improved internal penetration testing methodologies and delivery processes, increasing consistency and quality of engagements
• Delivered actionable, risk-based reporting to both technical and executive stakeholders.

Technical Administrator - Security

Gemeente Haarlem - Full-time

Apr 2021 - Sep 2025

Led security operations across multiple domains: PAM, WAF, vulnerability management, and MDR

• Acted as primary security authority for web application and access control domains
• Advised on security strategy, compliance (NIST, BIO), and risk management
• Supported M&A security due diligence and integration efforts
• Improved operational processes and security workflows across the organization

Cyber Security Engineer

BlackfishID - Remote, Part time

Jun 2025 - Oct 2025

As a Cyber Security Engineer at BlackfishID, I hold a key role in shaping and securing the organization's digital infrastructure. My responsibilities include:

Serving in an advisory capacity on cybersecurity architecture and infrastructure strategies.

• Providing technical guidance on the development and enhancement of existing systems.
• Managing and maintaining key components within Microsoft Azure, including Azure Functions, Defender for Cloud, Virtual Machines, and Entra ID.
• Offering expert analysis and recommendations on vulnerability management and threat mitigation.
• Implementing cybersecurity solutions and integrating various SaaS platforms for enhanced security and operational efficiency.
• Acting as a Technical Administrator to support and maintain secure environments.

MBO 4 Applicatie ontwikkelaar

Offensive Security Certified Professional +