I work in security and network operations, and in my own time I build labs:
networks to attack, then defend. Firewalls, IPS rules, WAFs and kernel hardening.
This site is my notebook: what I tried, what broke, and what I learned.
Good primitives are not a secure system. What a security audit of my own Python password manager found, how version 2 is designed, and five bugs that only appeared when I ran it.
Python · Argon2id · AES-256-GCM · PySide6 · Windows & Linux
A password manager that keeps everything in one encrypted file on your own disk:
no cloud, no telemetry, one runtime dependency. Version 2 is a ground-up rewrite
that followed a security audit of my own first version.
Argon2id calibrated per machine, a random vault key, and AES-256-GCM over all data, so even site names stay encrypted
Tamper-evident file format with a written specification and threat model
Clipboard auto-clear kept out of Windows clipboard history, TOTP codes, password-health audit
CLI and desktop app; 300+ tests, including official RFC test vectors and bit-flip property tests
A virtualized 3-tier topology (gateway, internal network, DMZ) with NAT and
"default deny" iptables policies, plus a ModSecurity web application firewall
blocking Layer 7 attacks such as XSS.
IPS & deep packet inspection
Snort · inline mode (NFQUEUE) · custom rules
Snort running inline through NFQUEUE, with custom rules that block Nmap stealth
scans, brute-force attempts and denial-of-service traffic.
Threat simulation & mitigation
Kali · hping3 · Hydra · Siege · SYN cookies
In my own virtual lab: SYN/ICMP floods and brute-force attacks generated with
Kali tools, then mitigated with kernel-level defenses such as SYN cookies.
about
I go by viot online. I have more than a year of hands-on experience
across network and security operations, helpdesk support and system administration.
Today I work as a Security & Network Operations Engineer, running Fortinet
firewalls and Juniper devices, triaging alerts in a 24/7 environment, and
automating the repetitive parts with Python.
Alongside work I am studying for an MSc in Cybersecurity & Data Science at the
University of Piraeus. My interests are network security, digital forensics and
embedded/IoT security, and I learn best by building something, breaking it, and
writing it down.