This repository is a documentation/runbook, not a software application. It teaches how to secure a Linux server through a long, well-organized markdown guide aimed primarily at Debian-based systems. The content covers SSH key authentication and sshd_config hardening, PAM-based 2FA/MFA and password quality, UFW firewall configuration including Docker interactions, intrusion detection/prevention with fail2ban, CrowdSec, and PSAD, and auditing tools such as AIDE, ClamAV, rkhunter, chkrootkit, logwatch, Lynis, and OSSEC. It also includes a separate kernel sysctl hardening reference table and a short nginx security headers guide. In production, the repository itself does not run anything; its value is the curated collection of copy-paste-ready shell commands, configuration snippets, and operational guidance that a human administrator applies to a server. The architecture is a set of static markdown files with a consistent section pattern (Why, How It Works, Goals, Steps, References), backup-before-edit conventions, and validation steps after changes. The main README is effectively an evolving security runbook with a detailed table of contents, while the auxiliary markdown files serve as standalone reference assets. Recent updates show active maintenance: the guide has been revised for Debian 13 systemd-timesyncd, OpenSSH 9.1 RSA size enforcement, Docker and UFW bypass caveats, and CrowdSec installation. However, some older recommendations remain dated—for example, certain sysctl keys in the hardening table are obsolete or no longer present in modern kernels, and several linked references are from 2018-2019. Because this is a documentation repository rather than executable code, quality assessment focuses on information architecture, practical utility, and reusability rather than software engineering structure.
This is a single-file Bash script that performs a comprehensive security and performance audit of a Linux VPS. It checks SSH configuration, firewall status, intrusion prevention systems (Fail2ban/CrowdSec), failed login attempts, system updates, running services, open ports, disk/memory/CPU usage, sudo logging, password policy, and SUID files. The script outputs color-coded PASS/WARN/FAIL results to the console and writes a detailed timestamped report to a file. It is designed for Ubuntu/Debian-based systems and requires root or sudo privileges. The architecture is a monolithic Bash script with no external dependencies beyond standard Linux utilities and optional tools like UFW, Fail2ban, and Docker. The code is well-structured with configurable thresholds and file paths, demonstrating solid Bash scripting practices. However, it is not designed for reuse as a library; it is a standalone tool.
LinuxGun is a collection of Bash shell scripts for Linux security incident response and system hardening. The core scripts (`linuxGun.sh`, `linuxGunPro.sh`, `linuxcheck.sh`) perform comprehensive checks across system information, user accounts, network connections, processes, files, logs, backdoors, tunnels, webshells, malware, memory, hacker tools, kernel modules, Kubernetes, and baseline security configurations. The toolset is designed for emergency triage by system administrators and security analysts, with color-coded output and modular function organization. It includes auxiliary tools for IP blocking (`blockIP.sh`), network interface monitoring (`monitorInter.sh`), process-to-IP connection mapping (`monitorPs2Ip.sh`), and a file upload server (`uploadServer.py`) for transmitting results. The repository also contains AI skill definitions (in `AI-skills/old/`) that describe an automated incident response workflow via SSH, though these appear to be experimental or deprecated. The codebase is functional but shows signs of rapid iteration, hardcoded assumptions (CentOS 7, specific command availability), incomplete modules, and mixed-language comments (Chinese/English). It is not a polished library but a practical, field-tested toolkit for Linux forensics.