reiderer
Hi, I'm Juan Rodríguez
Systems · Cloud · Cybersecurity · Blue Team → Red Team
I live between systems and security. I build labs, document what I learn and share the journey. This is my home: where I tell who I am and keep a record of what I build.
About me
I’m Juan Rodríguez Castellano and I live between two worlds I love: systems and cybersecurity.
I come from systems administration (ASIR) and it’s where I feel at home: networks, Windows and Linux, virtualization, Microsoft 365, Entra ID, cloud... building things, understanding how they fit together and keeping them running. I never want to let that part go.
Cybersecurity came later, almost by accident. It started as curiosity with an ethical hacking course, became a hobby and ended up a passion. Today I work mostly on Blue Team —detection, response, SIEM— and look eagerly toward Red Team and the OSCP.
For me systems and security always go together. I use reiderer as my place to build labs, document what I learn and share the journey.
And if there’s one thing I’m sure of, it’s that this isn’t about piling up tools, alerts or dashboards, but about understanding things well and telling signal from noise.
Projects & Labs
What I build, across my three areas: systems (my base), defense and offense. Labs close to a real environment, not demos.
High Availability Cluster
High-availability cluster with Pacemaker and Corosync on Linux, with MariaDB load balancing and automatic failover.
View documentation →Microsoft 365 deployment at scale
Real migration of 230+ endpoints with Windows Autopilot, Entra ID and Intune in a corporate environment.
Systems homelab
Virtualization with Proxmox, Active Directory, network services and automation. To keep growing in the systems side I love.
Wazuh SIEM Lab
Full Wazuh lab with a monitored Metasploitable3 and Kali as the offensive box. MITRE ATT&CK detection, 22 CVEs with CVSS prioritization, custom XML rules and VirusTotal API integration.
View on GitHub →Microsoft Sentinel Lab
Cloud-native lab in Azure: log ingestion, 5 KQL analytic rules mapped to MITRE ATT&CK and validation with controlled events. Where my two worlds meet: cloud and security.
DarkHole: 1
Web enumeration, SQL injection and privilege escalation via SUID binaries, with internal service analysis.
View write-up →Psycho: 1
Thorough enumeration, LFI exploitation, log analysis and privilege escalation through scripts with special permissions.
View write-up →Road to OSCP
The next chapter: more boxes, more offensive labs and progress toward the OSCP. In red, because that’s the direction.
Blog
reiderer is, above all, a log. Here I post what I learn, what I build and what I think about systems and security.
One year in cybersecurity: telling signal from noise
A year ago I didn’t know what a SIEM was. A look back at the road and the lesson I value most.
Blue TeamBuilding a Microsoft Sentinel lab: less is more
The most useful part of building the lab wasn’t the detections, but deciding what made sense to include.
How I work
I work the same way building a system as investigating an alert: understand first, prioritize and document everything well.
Understand before touching
Before launching anything, I try to understand what the system exposes, how it’s built and the context around it.
Prioritize, don’t pile up
I don’t obsess over having more rules or more sources. I prefer fewer things, but understood in depth.
Correlate over time
An isolated alert is usually a medium signal. The real value is how several signals fit together.
Document the process
I care about leaving work well documented: reviewable, reproducible and easy to explain.
Connect systems and security
I understand how infrastructure is built and how it’s defended. That full context is my biggest advantage.
Experience
Certifications
I certify what I learn. Right now the focus is Microsoft Security; in the future, the OSCP.
SC-200
Plus more training in ethical hacking, malware analysis and OT security. On the horizon: SC-200, AZ-104, AZ-500 and OSCP.
Recommendations
From the start of ASIR, Juan showed great interest in cybersecurity. He always went a step further, learning on his own. Very dynamic, with a constant drive to improve.
Juan stood out for his interest and curiosity in cybersecurity. Always learning on his own, beyond class. Very proactive and eager to keep improving.
Let's talk systems and security
reiderer is my place to share what I do and what I learn. If you want to comment, propose a collaboration or just connect, here I am.