Security Manual AgentHub

AgentHub Server absichern / Securing AgentHub Server

1. Overview / Übersicht

The basis for our AgentHub software on the VPS server is Linux with the following components:

Component	Purpose
OpenClaw	AI agents
Apache2	Webserver for websites
WordPress	Required for AgentHub plugin
Nextcloud (optional)	Used for appointment booking
Linux	Operating system

This manual covers securing all five software components.

2. General / Allgemeines

Webmin Installation

For better administrative overview, install Webmin:

sudo apt-get install webmin

Access via: https://your-server-ip:10000

3. WordPress Security

Recommended Software

Loginizer Pro (recommended)
OR alternatively: Wordfence

Optional: IP Region Blocking

# iptables to exclude IP regions (optional)

4. Nextcloud Security

Data Directory

Data directory outside of Nextcloud installation:

# /var/nextcloud-data (instead of /var/www/nextcloud)

Owner and Rights

Path	Owner	Rights
`/var/www/nextcloud/`	`root:www-data`	`0755`
`/var/www/nextcloud/config/config.php`	`root:www-data`	`0640`
`/var/nextcloud-data`	`www-data:www-data`	`0770`

App Installation (Terminal)

Since with these rights Nextcloud apps cannot be installed via browser, install apps in terminal:

Calendar App Example:

sudo php /var/www/nextcloud/occ app:install calendar

List all installed apps:

sudo -u www-data php /var/www/nextcloud/occ app:list

Update app:

sudo -u www-data php /var/www/nextcloud/occ app:update calendar

5. OpenClaw Security

Known Vulnerabilities

Vulnerability	Description
RCE (CVE-2026-25253)	Critical remote code execution
Malicious Skills	Community skills contain malware
Exposed Gateways	Unsafe Docker defaults expose ports
Prompt Injection	Hidden instructions manipulate AI
Plain Credentials	API keys stored in plaintext

5.1 Strict Localhost-Binding & SSH-Tunneling

Problem: Websocket ports (8000/8080) open to internet.

Solution:

# Configure OpenClaw to ONLY listen on 127.0.0.1 (NOT 0.0.0.0)

Access via SSH-Tunnel:

ssh -L 8000:127.0.0.1:8000 user@vps-ip

This keeps ports completely closed from outside.

5.2 Systemd Sandbox

Create global service:

sudo nano /etc/systemd/system/openclaw-gateway.service

Service content:

[Unit]
Description=OpenClaw Gateway Protected System Service
After=network-online.target

[Service]
Type=simple
User=claw
Group=claw
WorkingDirectory=/home/claw
Environment=PATH=/home/claw/.npm-global/bin:/usr/local/bin:/usr/bin:/bin
ExecStart=/home/claw/.npm-global/bin/openclaw gateway run
Restart=always

# ==========================================
# SYSTEMD HARDENING (RCE-SCHUTZ)
# ==========================================
ProtectSystem=strict
ProtectHome=read-only
ReadWritePaths=/home/claw/.openclaw
PrivateTmp=true
NoNewPrivileges=true
CapabilityBoundingSet=~CAP_SYS_ADMIN ~CAP_SYS_CHROOT ~CAP_NET_ADMIN

[Install]
WantedBy=multi-user.target

Enable service:

# Stop old user service
systemctl --user stop openclaw-gateway.service
systemctl --user disable openclaw-gateway.service

# Reload systemd
sudo systemctl daemon-reload

# Start new system service
sudo systemctl start openclaw-gateway.service
sudo systemctl enable openclaw-gateway.service

5.3 Firewall (UFW)

ufw default deny incoming
ufw default allow outgoing
ufw allow from [Firmen-IP] to any port 22 comment 'SSH nur für die Firma'
ufw enable

5.4 Update Handling

After every OpenClaw update, check for ghost instances:

# After updates always run to block user service:
systemctl --user stop openclaw-gateway.service 2>/dev/null
systemctl --user disable openclaw-gateway.service 2>/dev/null

6. SSH Key Authentication

Ed25519 Key Setup

Step 1: Create key pair (local PC):

ssh-keygen -t ed25519 -C "vps-zugang"

Press Enter three times.

Step 2: Copy public key to VPS:

ssh-copy-id user@vps-ip

OR manually copy content to ~/.ssh/authorized_keys.

Step 3: Anti-lockout test

Open a separate terminal window:

ssh user@vps-ip

If login succeeds without password, test was successful.

Step 4: Disable password login (VPS):

sudo nano /etc/ssh/sshd_config

Add/modify:

PasswordAuthentication no
PubkeyAuthentication yes
ChallengeResponseAuthentication no
KbdInteractiveAuthentication no

Restart SSH:

sudo systemctl restart ssh

7. Fail2Ban Integration

7.1 Installation via Webmin

In Webmin go to: Unused Modules → Fail2Ban Intrusions Detector

Click: Install Now

7.2 Nextcloud Filter

sudo nano /etc/fail2ban/filter.d/nextcloud.conf

Content:

[Definition]
_groupsre = (?:(?:,?\s*"\b\w+\b":(?:"[^"]*"|\d+))*)
failregex = ^\{%(_groupsre)s\s*"message"\s*:\s*"Login failed:\s*[^"]*"\s*%(_groupsre)s\s*,\s*"remoteAddr"\s*:\s*"<HOST>"%(_groupsre)s\s*\}$
 ^\{%(_groupsre)s\s*"remoteAddr"\s*:\s*"<HOST>"%(_groupsre)s\s*,\s*"message"\s*:\s*"Login failed:\s*[^"]*"%(_groupsre)s\s*\}$

Create jail:

sudo nano /etc/fail2ban/jail.local

7.3 Webmin Auth Filter

In Webmin:

Go to: Fail2Ban Module → Filters → Actions → Jails
Find: webmin-auth
Enable: Yes

7.4 OpenClaw Filter (Optional)

Only needed if OpenClaw is exposed via internet.

Filter creation:

Filter name: openclaw
Failregex:
^.*"level":"error".*"message":".*unauthorized.*".*"ip":"<HOST>".*$
^.*"level":"warn".*"message":".*auth failure.*".*"ip":"<HOST>".*$

Jail settings:

Setting	Value
Filter	openclaw
Log path	`/home/claw/.openclaw/logs/openclaw.json`
Port	8000/8080
Max retries	5
Ban time	7200 seconds

8. WordPress Integration

8.1 WP Fail2Ban Plugin

Filter creation:

Filter name: wordpress
Failregex:
<HOST>.*POST.*(wp-login\.php|xmlrpc\.php|account\/signin).* 200

Jail settings:

Setting	Value
Log path	`/var/log/apache2/access.log`
Port	http,https
Max retries	3
Ban time	86400 (24 hours)

8.2 Loginizer Extension

Add additional protection:

Regex extension:

<HOST>.*POST.*(wp-login\.php|xmlrpc\.php).* (200|403|302)

Effect:

Loginizer blocks bot (403)
Fail2ban counts request immediately
IP blocked after 3 requests

8.3 Hide Login Function

Activate in Loginizer:

Change wp-admin login URL to secret address
99% of bots run into empty
Server load reduced immediately

9. Quick Reference

Component	Protection Method
Webmin	Fail2Ban webmin-auth jail
OpenClaw	Systemd sandbox, SSH tunnel
Nextcloud	Fail2Ban filter + jail
WordPress	Loginizer Pro, Fail2Ban, Hide Login
SSH	Ed25519 keys, password disabled

Stand / Status: 2026-07-06