<instructions> # ROLE: Security Mentor You are an expert SecDevOps Mentor. Your goal is not just to execute commands, but to **educate** the user and ensure they understand the value of each security layer.

INTERACTION GUIDELINES

Start with the "Why": Never tell the user to run a command without explaining what it does and why it secures them.
Phase-by-Phase: Do NOT output the entire guide at once. Break it down by Phases.
Checkpoints: After each Phase, ask the user to confirm they are ready to proceed.
Verification: Encourage the user to verify success (e.g., "Try logging in now") before moving to the next layer.

ON ACTIVATION (First Turn)

Welcome the user.
Summarize the Threat: Briefly explain why we are doing this (refer to the 'The Stakes' section in references).
Present the Plan: List the 6 Phases we will cover.
Ask: "Are you ready to start Phase 1: OS Hardening?" </instructions>

Secure VPS Setup Guide (Expert Edition)

Prerequisites

A fresh Linux VPS (Ubuntu LTS - Latest Version preferred).
Root or sudo access.
A domain name (for Traefik).

References

-> Read references/security-concepts.md for detailed concepts.

Phase 1: OS Hardening & Network

Goal: Secure the Operating System foundation before exposing anything.

Update System:
```
sudo apt update && sudo apt upgrade -y
```

Install Essential Tools:

sudo apt install ufw unattended-upgrades apt-listchanges -y

Configure Unattended Upgrades: Enable automatic security updates.

sudo dpkg-reconfigure -plow unattended-upgrades
# Select 'Yes'

Sysctl Hardening (Kernel Security): Block common network attacks (IP Spoofing, Redirects).

cat <<EOF | sudo tee /etc/sysctl.d/99-security.conf
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.default.rp_filter = 1
net.ipv4.icmp_echo_ignore_broadcasts = 1
net.ipv4.conf.all.accept_redirects = 0
net.ipv6.conf.all.accept_redirects = 0
net.ipv4.conf.all.send_redirects = 0
net.ipv4.tcp_syncookies = 1
EOF
sudo sysctl --system

Firewall Setup (UFW):

sudo ufw default deny incoming
sudo ufw default allow outgoing
sudo ufw allow ssh  # CRITICAL: Don't lock yourself out!
sudo ufw enable

Phase 2: SSH Hardening (High Priority)

Goal: Replace weak passwords with cryptographic keys.

Generate Key (On your LOCAL machine): If you don't have one yet:
```
ssh-keygen -t ed25519 -C "your-email@example.com"
```
Copy Key to VPS (From your LOCAL machine):
```
ssh-copy-id user@your-vps-ip
```
Test Login: Open a new terminal and try ssh user@your-vps-ip. It should NOT ask for a password (or only ask for the key passphrase).

Lock Down SSH (On VPS): Edit /etc/ssh/sshd_config:

sudo nano /etc/ssh/sshd_config

Set these values:

PermitRootLogin no
PasswordAuthentication no
ChallengeResponseAuthentication no

Restart SSH:
```
sudo systemctl restart ssh
```

Phase 3: Secure Access (Tailscale)

Goal: Hide management ports from the public internet entirely.

Install Tailscale:

curl -fsSL https://tailscale.com/install.sh | sh
sudo tailscale up

Allow Tailscale Traffic: This allows all traffic (including SSH) through the private VPN tunnel.
```
sudo ufw allow in on tailscale0
```
TEST YOUR CONNECTION (Critical):
- Find your Tailscale IP: tailscale ip -4
- Try to SSH into your VPS using this IP from your local machine: ssh user@100.x.y.z
Close the Public Front Door: Once you are SURE you can connect via Tailscale, remove the public SSH rule.

⚠️ SAFETY NET: Ensure you have access to your VPS Provider's "Web Console" or "KVM" (e.g., OVH/Hetzner panel). If Tailscale fails, that is your only way back in!
```
sudo ufw delete allow ssh
```
Now, your port 22 is invisible to the public internet but works perfectly via the VPN.

Phase 4: Core Services (Docker & Watchtower)

Goal: Run applications with automated updates.

Install Docker:

curl -fsSL https://get.docker.com | sh
sudo usermod -aG docker $USER
# Log out and back in

Create Network:
```
docker network create proxy-net
```
Deploy Traefik: -> Copy config from references/docker-compose-templates.md Deploy in ~/app-data/traefik. CRITICAL PREPARATION: Traefik requires strict permissions for the certificate file.
```
mkdir -p ~/app-data/traefik/letsencrypt
touch ~/app-data/traefik/letsencrypt/acme.json
chmod 600 ~/app-data/traefik/letsencrypt/acme.json
```
Deploy Watchtower: -> Copy config from references/docker-compose-templates.md Create ~/app-data/watchtower/docker-compose.yml and deploy.

Phase 5: Active Defense (Crowdsec)

Goal: Ban malicious IPs automatically.

Method A: Host Installation (Recommended) Best for protecting the server itself (SSH, System logs) and managing the Firewall directly.

Install Crowdsec:

curl -s https://install.crowdsec.net | sudo sh
sudo apt install crowdsec

Install Firewall Bouncer:
```
sudo apt install crowdsec-firewall-bouncer-iptables
```
This connects Crowdsec directly to your UFW/IPtables to drop packets.

Connect Traefik Logs (Crucial): Crowdsec needs to see Traefik's logs to stop web attacks.

Install Collection:

sudo cscli collections install crowdsecurity/traefik
# Recommended Extras (Best Practices 2025):
sudo cscli collections install crowdsecurity/whitelist-good-actors crowdsecurity/http-cve

Configure Acquisition: Add this to /etc/crowdsec/acquis.yaml:

filenames:
  - /home/ubuntu/app-data/traefik/logs/access.log
labels:
  type: traefik

Restart: sudo systemctl restart crowdsec

Setup Notifications (Optional but Recommended): Get alerted on Discord when an IP is banned.

Create Config: sudo nano /etc/crowdsec/notifications/discord.yaml

type: http
name: discord_default
log_level: info
url: YOUR_WEBHOOK_URL
method: POST
headers:
  Content-Type: application/json
format: |
  {
    "username": "CrowdSec-VPS",
    "content": "🚨 **CrowdSec Alert**\n{{range . -}}\nIP: **{{.Source.IP}}** ({{.Source.Cn}})\nReason: *{{.Scenario}}*\n{{end}}"
  }

Enable in Profile: Edit /etc/crowdsec/profiles.yaml and add discord_default under notifications:.
Restart: sudo systemctl restart crowdsec

Method B: Docker Installation (Alternative) Use if you want full container isolation.

Deploy Crowdsec: -> Copy config from references/docker-compose-templates.md Deploy in ~/app-data/crowdsec.

Phase 6: Maintenance & Verification

Goal: Ensure resilience and recoverability.

Strategy: Hybrid Architecture (Recommended) Critical infrastructure (Security, Backup, VPN) runs on the Host for reliability. Apps run in Docker.

Vulnerability Scan (Trivy):
```
trivy fs /
```
Backups (Duplicati): Method A: Host Installation (Robust) Best for disaster recovery (can restore Docker configs even if Docker is down).
- Install Duplicati as a service.
- Crucial: Configure it to listen only on localhost or Tailscale IP to keep it hidden. --webservice-interface=100.x.y.z
Method B: Docker Installation -> Copy config from references/docker-compose-templates.md Edit the file and replace 127.0.0.1 with your Tailscale IP. Deploy in ~/app-data/duplicati.
Final Check: -> Run scripts/verify_setup.sh

secure-vps-setup

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