About

Cybersecurity professional based in Brussels, working across the full offensive stack. Below is the same session that runs on the homepage: skip ahead or replay it at any time. Everything after it is the long-form version.

selim@portfolio:~$ whoami
Selim Celebi — Cybersecurity professional
Brussels, Belgium · available for offensive security roles

selim@portfolio:~$ cat profile.txt
I break things to understand how they hold together.

Graduated Cum Laude from Howest in Applied Computer Science –
Cyber Security Professional. I work across the full offensive stack:
web and network pentesting, malware analysis, reverse engineering
and digital forensics.

selim@portfolio:~$ ls -la experience/
EUROCONTROL — EATM-CERT trainee (Feb–May 2025, Brussels)
  › Co-engineered an aviation CTF for 113 players across the
    European aviation sector
  › Penetration testing of aviation systems and applications
  › R&D supporting aviation cybersecurity

selim@portfolio:~$ cat projects.md
Security audit      full audit for a company and a pharmacy —
                    OSINT, pentest, phishing simulation, awareness survey
Honeypot lab       honeypot servers + Kibana dashboards, red vs blue
Mobile security    deliberately vulnerable Android app for pentest training
Pentest report     full network and system audit with mitigation strategy

selim@portfolio:~$ ctf --stats
Hackfinity Battle 2025     TryHackMe    top 7%  #295 / 4356
Cyber Apocalypse 2025      HackTheBox   top 8%  #614 / 8129
Cyber Security Challenge   Belgium      4 editions 2023–2026
Hack the Future            Antwerp      2024

selim@portfolio:~$ cat skills.json
{
  "offensive": ["web pentesting", "network & system pentesting"],
  "analysis":  ["malware analysis", "reverse engineering", "forensics"],
  "code":      ["Java", "C", "C++", "C#", "Kotlin", "SQL", "Bash"],
  "systems":   ["Linux", "Windows Server", "Git", "CCNA"],
  "languages": ["FR native", "TR native", "EN C1", "NL B1"]
}

selim@portfolio:~$ contact --show
email     via the contact form — no plaintext address published
linkedin  /in/celebiselim
blog      write-ups & event notes

Thanks for reading. Say hi.

Background

I graduated Cum Laude from Howest in Applied Computer Science with a specialisation as Cyber Security Professional. The course covered both halves of the discipline, building systems properly and then taking them apart, and I gravitated firmly toward the second half.

My final internship was at EUROCONTROL’s EATM-CERT in Brussels, the computer emergency response team for European air traffic management. Over four months I co-engineered an aviation-themed capture-the-flag competition that ran for 113 players from across the European aviation sector, carried out penetration testing against aviation systems and applications, and contributed to research supporting aviation cybersecurity.

Selected work

Full security audit: company and pharmacy

An end-to-end engagement for two real organisations: OSINT reconnaissance, technical penetration testing, a controlled phishing simulation, and a staff awareness survey. Delivered as a report with prioritised findings and a mitigation strategy the client could actually act on.

Honeypot laboratory

Deployed honeypot servers instrumented with Kibana dashboards, then ran the environment as a red-versus-blue exercise. Watching real automated traffic hit an exposed host teaches you more about attacker behaviour than any lab exercise.

Deliberately vulnerable Android application

Built a mobile application seeded with realistic flaws (insecure storage, weak authentication, poor certificate handling) for use as a mobile pentest training target.

Network and system penetration test

A full infrastructure audit covering network and host layers, documented as a professional pentest report with a mitigation strategy per finding.

Competitions

• TryHackMe Hackfinity Battle 2025: top 7%, ranked #295 of 4356.
• HackTheBox Cyber Apocalypse 2025: top 8%, ranked #614 of 8129.
• Cyber Security Challenge Belgium: four editions, 2023 to 2026.
• Hack the Future 2024, Antwerp: Mission Among the Stars.
• Belgium’s Best Ethical Hacker 2024: live exploitation against a scored range.

Technical

Offensive: web application pentesting, network and system pentesting, phishing simulation, OSINT.
Analysis: malware analysis, reverse engineering, digital forensics.
Languages: Java, C, C++, C#, Kotlin, SQL, Bash.
Systems: Linux, Windows Server, Git, CCNA-level networking.
Spoken: French and Turkish native, English C1, Dutch B1.