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docs/security.md

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+# Security guidance
+
+This project can perform security-sensitive operations (bans, configuration changes). Deploy it as you would deploy every other administrative interface.
+
+## Recommended deployment posture
+
+- Do not expose the UI directly to the Internet.
+- Prefer one of:
+  - VPN-only access
+  - Reverse proxy with strict allowlists
+  - OIDC enabled (in addition to network controls)
+
+If you must publish it, put it behind TLS and an authentication layer, and restrict source IPs.
+
+## Callback endpoint protection
+
+The fail2ban callback endpoints (`/api/ban`, `/api/unban`) are only reachable with a correct `CALLBACK_SECRET`. This secret must be atleast 20 characters long. If not specified a secure secret, will be automatically genereated on first start. It can be further protected by:
+
+- Use even a stronger `CALLBACK_SECRET` than our default (32 characters)
+- Make network restrictions (only allow known Fail2Ban hosts to reach the callback endpoint)
+
+Rotate the secret if you suspect leakage.
+
+## SSH connector hardening
+
+For SSH-managed hosts:
+
+- Use a dedicated service account (not a human user).
+- Require key-based auth.
+- Restrict sudo to the minimum set of commands required to operate Fail2Ban (typically `fail2ban-client` and optionally `systemctl restart fail2ban`).
+- Use filesystem ACLs for `/etc/fail2ban` rather than broad permissions to allow full modification capabilities for the specific user.
+
+## Least privilege and file access
+
+Local connector deployments typically require access to:
+- `/var/run/fail2ban/fail2ban.sock`
+- `/etc/fail2ban/`
+- selected log paths (read-only, mounted to same place inside the container, where they are on the host.)
+
+Avoid running with more privileges than necessary. If you run in a container, use the repository deployment guide and SELinux policies.
+
+## SELinux
+
+If SELinux is enabled, use the policies provided in (according to your specific setup they are not enough):
+- `deployment/container/SELinux/`
+
+Do not disable SELinux as a shortcut. Fix always labeling and policy issues instead. -> Everytime you read "to disable SELinux" you can close that guide :)
+
+## Audit and operational practices
+
+- Back up `/config` (DB + settings) regularly.
+- Treat the database as sensitive operational data.
+- Keep the host and container runtime patched.
+- Review Fail2Ban actions deployed to managed hosts as part of change control.