Network & IT Securityネットワーク＆ITセキュリティ

LNXE Corp — a secure virtualised infrastructure

For a fictional ten-person software start-up, I designed, built and tested the whole IT environment in VMware Workstation Pro: two hardened Ubuntu servers (an Nginx web server and a separate backup server), Linux and Windows 11 clients, and a segmented wired and wireless network, documented in Cisco Packet Tracer.

• Network design with an IP plan and segmentation (internal LAN and NAT) to limit lateral movement.
• Hardening: minimal installs, SSH with keys only (no passwords), least-privilege users, file permissions, patching, host firewall rules with UFW, logging.
• Backups with rsync over SSH, plus a real restore test, and recovery targets (RTO and RPO) with ransomware in mind.
• Risk analysis (external, internal and wireless threats) and a defence-in-depth model from the hardware layer to the people using it.
• Everything validated: connectivity, SSH attacks, firewall rules, backup and restore, wireless security.

The network as built: servers and clients on an isolated internal LAN, NAT only for updates, and backups that only the web server can reach.

NordTech Solutions — analysing a data breach

A report on a spear-phishing attack at a Norwegian cloud company: how stolen credentials let the attacker in, which security practices failed, and what it means legally and ethically.

• GDPR assessment: breach notification, data subjects' rights, the company's obligations.
• A rewritten IT security policy for the company, and recommendations against the next attack.
• Ethics through Kantian and utilitarian lenses, and the cybercrime laws that apply to the attackers.