Sentry42

// blue team · 42 Paris

Infosec student at 42Paris school. Focusing on blue teaming, taste for threat hunting and threat intelligence.

// WHOAMI //

I’m Sentry42, an IT security student at 42Paris, and I’m all in on blue teaming, in all its forms, from day-to-day security operations to the bigger strategic picture.

The Watch Node is where I share what I learn, explore and question along the way, whatever the corner of the field it comes from.

// ORIGIN //

It started at a conference where incident responders walked through the aftermath of an attack on a well-known French company. I didn’t get everything at the time, but that was enough: I wanted to understand. I wanted to be the person who could read the whole story from the traces an attacker leaves behind.

Looking back, it made sense. I’ve always loved solving mysteries: understanding what wants to stay hidden, untangling what seems impossible to make sense of. And I love protecting what matters from people who don’t wish it well. Defensive security turned out to be exactly where those two meet.

My first real step was HTB University CTF 2022, where my team finished 4th worldwide out of 2,500+ teams. That pushed me to take on the presidency of APT42, the 42Paris infosec association (not that kind of APT, okay), where we ran workshops, CTF sessions and a lot of peer-to-peer learning.

// FIELD EXPERIENCE //

After wrapping up the 42Paris common core in November 2023, I spent a year as an intern on the security operations team of a major satellite company, an environment where sensitive information is the norm. I got to see every role of a SOC from the inside, but my real mission was to hunt for nation-state APTs. It was exciting, technical and impactful, it changed how I look at defence: I learned to think like the adversary I’m hunting. I discovered how much depth there was to it, how technical it could get, and how much was possible. I came out wanting to learn more, train harder, and with one certainty: this is exactly what I want to do.

I then chose to continue with an apprenticeship as an L1-L2 SOC Analyst at an MSSP with a wide range of clients. That choice was deliberate as I’m convinced you can’t really understand blue teaming without being on the front line. Every day there brings real experience, and with it new questions, many of which end up on this blog.

// WHAT YOU’LL FIND HERE //

Blue Team Ops, Threat Hunting, Cyber Threat Intelligence, Artificial Intelligence and Writeups. Each one feeds the others: together, they build the wide-angle view you need to see what’s coming, and the precision to answer it.

// MISSION //

Keep practicing, keep reading, keep writing (when time allows it), until I’m good enough to hold the line against the most sophisticated threats out there.

If something here helped you, or you think I got something wrong, I’d genuinely like to hear about it (sentry42@proton.me). I also put some of my crazy creative ideas in this blog’s design (explore), I hope you’ll appreciate it :) Thank you !