TREK/wiki/Security-Hardening.md

Security Hardening

A production TREK deployment checklist. All items reference actual TREK configuration options.

Encryption & Secrets

• Set a strong ENCRYPTION_KEY (generate with openssl rand -hex 32). See Encryption-Key-Rotation.
• Back up ENCRYPTION_KEY separately from the database backup ZIP — losing it makes all stored API keys and secrets unreadable. Stored secrets use AES-256-GCM encryption derived from this key.
• Rotate ENCRYPTION_KEY if it may have been exposed. See Encryption-Key-Rotation.

HTTPS & Network

• Run TREK behind a TLS-terminating reverse proxy (nginx, Caddy, Traefik). See Reverse-Proxy.
• Set TRUST_PROXY=1 so client IPs are captured correctly in the audit log. In NODE_ENV=production this defaults to 1 automatically, but set it explicitly if you use a non-standard proxy hop count.
• Set FORCE_HTTPS=true to 301-redirect HTTP to HTTPS and add upgrade-insecure-requests to the CSP. Your proxy must send X-Forwarded-Proto: https (or terminate TLS on the same connection), otherwise the redirect fires on every request and loops.
• Know that HSTS (max-age=31536000) does not depend on FORCE_HTTPS: it is sent whenever FORCE_HTTPS=true or NODE_ENV=production, which the Docker image sets by default — so an instance behind Traefik, Caddy or a Cloudflare Tunnel advertises HSTS without setting FORCE_HTTPS at all. Set HSTS_INCLUDE_SUBDOMAINS=true to add includeSubDomains; it is off by default so an install on an apex domain does not force HTTPS onto sibling subdomains you may still serve over plain HTTP.
• Keep ALLOW_INTERNAL_NETWORK=false unless Immich or Synology is on your LAN. See Internal-Network-Access. Note: loopback (127.x, ::1) and link-local (169.254.x) addresses are always blocked regardless of this setting.

Authentication

• Enable two-factor authentication for your admin account. See Two-Factor-Authentication.
• Require MFA for all users if your use case demands it: Admin Panel → Settings → Require two-factor authentication (2FA). Note: you must secure your own admin account first, with either TOTP or a registered passkey — the server refuses the toggle otherwise. A passkey satisfies the policy for everyone else too, so nobody is forced onto TOTP specifically.
• Disable open registration if you control who can access the instance. See Admin-Users-and-Invites.
• Rotate the JWT signing secret if a session may have been leaked: Admin Panel → Settings → Danger Zone → Rotate (POST /api/admin/rotate-jwt-secret). This invalidates all active sessions immediately, including your own.

Session Security

TREK stores sessions as JWTs in an httpOnly trek_session cookie (SameSite=Lax). A normal login expires after SESSION_DURATION (default 24 hours) and rides in a browser-session cookie that the browser drops when it closes; ticking Remember me issues a persistent cookie whose lifetime and JWT expiry are SESSION_DURATION_REMEMBER (default 30 days) — shorten it if a 30-day window is too wide for your threat model. The secure flag is set automatically when NODE_ENV=production, when FORCE_HTTPS=true, or when Express sees that the request arrived over TLS (X-Forwarded-Proto: https) — the last of those needs trust proxy active, which is automatic in production and otherwise means setting TRUST_PROXY yourself. Tokens are also accepted via Authorization: Bearer header for MCP and API clients.

• Ensure FORCE_HTTPS=true (or NODE_ENV=production) so the trek_session cookie carries the secure flag and is never sent over plain HTTP.
• Set COOKIE_SECURE=false only as a temporary escape hatch for LAN testing without TLS — do not use in production.

Password Policy

TREK enforces a minimum password policy on all registrations and password changes:

• Minimum 8 characters
• Must contain uppercase, lowercase, digit, and special character
• Common passwords and fully-repetitive strings are rejected
• Passwords are hashed with bcrypt (cost factor 12)

No configuration is required; this policy is always active.

Rate Limiting

Built-in in-memory rate limits protect authentication endpoints:

Endpoint	Limit	Window
Login / Register / Invite	10 attempts	15 minutes
MFA verify-login / enable	5 attempts	15 minutes
Password change	5 attempts	15 minutes
MCP token creation	5 attempts	15 minutes

These limits are per source IP. If TREK is behind a reverse proxy, set TRUST_PROXY so the real client IP is used rather than the proxy's IP.

Content Security Policy

Helmet applies a strict CSP on all responses. Key directives:

• default-src 'self'
• script-src 'self' 'wasm-unsafe-eval' 'unsafe-eval' (no unsafe-inline; 'unsafe-eval' is required by the in-browser HEIC converter, which initialises through new Function())
• object-src 'self' (so same-origin file previews can embed PDFs via <object>/<embed>)
• frame-src 'self' (for the sandboxed plugin frames at /plugin-frame/*, which run at an opaque origin under their own CSP)
• frameAncestors 'self' (prevents clickjacking from external frames)
• upgrade-insecure-requests (added automatically when FORCE_HTTPS=true)

Plugin Runtime Hardening

Installed plugins run untrusted third-party code. TREK contains a plugin in several independent layers so a hostile or buggy plugin can neither read TREK's data nor take the instance down. Nothing here needs configuration — it is all on by default — but the escape hatches below exist for tuning.

• Leave the plugin system's defaults in place. It is on by default but installed plugins still have to be activated one by one, so no third-party code runs until an admin turns a specific plugin on. Set TREK_PLUGINS_ENABLED=false (accepts false/0/off/no) to switch the whole system off — installed plugins stay on disk, deactivated, and the runtime is idle.
• Keep the OS permission jail enabled (the default). In production each plugin runs in an isolated child process launched with Node's --permission model: filesystem writes, child_process, worker threads and native addons are denied outright, and reads are scoped to just the plugin's own code — so a plugin cannot read trek.db or the secret files, or shell out. The child's environment is scrubbed (no JWT_SECRET, no DB credentials). Setting TREK_PLUGIN_PERMISSIONS=off disables this jail (isolation then falls back to crash-only) and logs a loud warning — only ever do this on a machine you fully trust.
• Rely on the private-egress block (SSRF backstop). Even a plugin that declared an outbound host cannot reach a destination that resolves to a loopback, private, link-local, ULA, carrier-grade-NAT, cloud-metadata (169.254.169.254), multicast or reserved address — the guard re-checks the resolved IP, so a plugin can't pivot to internal services or DNS-rebind to them. This is independent of ALLOW_INTERNAL_NETWORK (which only governs core Immich/Synology features). The one escape hatch is TREK_PLUGIN_ALLOW_PRIVATE_EGRESS=on, for a plugin that has to reach a service on your LAN (a Gotify, an ntfy, an Ollama). It is instance-wide rather than per plugin, and it lifts the block entirely rather than narrowing it: a declared host may then resolve to any address, the 169.254.169.254 metadata IP included, and unix-socket or named-pipe connects (docker.sock, a local database socket) are permitted without even being declared, since the OS jail does not gate socket connects. Leave it unset unless a specific plugin genuinely needs a LAN target.
• The supervisor caps each plugin's resident memory (default 300 MB, TREK_PLUGIN_MAX_RSS_MB) — measured host-side from the OS, never the plugin's self-report — and kills a plugin that blows the ceiling or stops sending heartbeats; repeat offenders auto-disable. Every ctx.* capability call is also rate-limited at the dispatch boundary (a token bucket: ~60-call burst, 20 calls/sec sustained, 16 concurrent; TREK_PLUGIN_RPC_BURST / TREK_PLUGIN_RPC_PER_SEC / TREK_PLUGIN_RPC_INFLIGHT), so one plugin in a tight loop gets throttled instead of freezing the instance.
• Review the capability audit if you grant plugins broad data access. Every host-mediated core-data read and broadcast a plugin makes is recorded at the RPC boundary against the real acting user (not a value the plugin supplies) in a per-plugin, hash-chained, tamper-evident log. Admins see it per plugin; each user can see "what have plugins done in my name?". Retention is capped per plugin (default 20 000 rows, TREK_PLUGIN_AUDIT_MAX_ROWS).

The developer dev-link feature (TREK_PLUGINS_DEV_LINK=1) loads unsigned local code and, under npm run dev, runs with the OS jail off — keep it off on any instance that isn't a throwaway dev box you control. See Plugins and Plugin Permissions.

Backups

• Enable auto-backup with an appropriate retention window. See Backups.
• Store backups off-site — copy backup ZIPs to a separate location outside the TREK host.

Monitoring

• Review the audit log periodically for unexpected logins or admin changes. See Audit-Log.
• Check for TREK updates regularly. See Admin-GitHub-Releases and Updating.

See also

• Encryption-Key-Rotation
• Reverse-Proxy
• Internal-Network-Access
• Two-Factor-Authentication
• Admin-Permissions
• Admin-Users-and-Invites
• Backups
• Audit-Log
• Admin-GitHub-Releases
• Updating
• Environment-Variables