Ubuntu Security

Ubuntu-Security is a collection of agent skills for host security on Ubuntu desktops and servers, written primarily in Shell. Each skill is a SKILL.md file containing working commands, and the skills cover the ufw firewall (first-time setup, status probing, scoped allow rules, removal, and diagnosis of blocked traffic), malware, rootkit, and integrity scanning with ClamAV, rkhunter, and related tools, and read-only security audits covering updates, exposure, SSH, accounts, permissions, and AppArmor. Additional skills address SSH key management and server configuration, fail2ban, YubiKey and fingerprint authentication, and scan scheduling through systemd timers with cron as a fallback. Helper scripts in a scripts directory perform log summarisation, scanner updates, scan execution with defined exit codes, and posture data collection.

The skills are designed to report facts and carry out the requested action without adding unrequested hardening advice, with audit skills responsible for listing findings. Where desktop and server environments differ, or where a remote SSH session requires caution, the relevant skill documents the difference. The project is written for Ubuntu 22.04 and later and is tested against Ubuntu 26.04 with ufw 0.36 and OpenSSH 10, with most commands also working on Debian. It stores plugin configuration and firewall baselines in a user data directory and writes scan and audit reports to a configurable reports folder, and it supersedes several earlier Claude plugins for Linux management.

This project may be useful to system administrators and Ubuntu users who want repeatable, command-driven security checks for firewall state, malware scanning, and configuration audits, and to developers building agent-based workflows for Linux host administration who want a reference for structuring SKILL.md-based tooling.