supabase-security

name	supabase-security
description	Use when auditing or hardening a Supabase project's security posture. Triggers: scan/audit Supabase, RLS verification, find leaky tables, check anon grants, review SECURITY DEFINER functions, prep for the May 30 / Oct 30, 2026 Data API exposure changes, generate remediation SQL. Works against any Supabase project (Cloud or self-hosted) given a Personal Access Token.
metadata	{"author":"Perufitlife","version":"0.1.0","homepage":"https://github.com/Perufitlife/supabase-security-skill"}

Supabase Security Skill

A pure-Node.js audit + remediation toolkit for Supabase projects. No dependencies, runs locally, your token never leaves your machine.

What it checks

1. Tables with RLS disabled + grants to anon/authenticated → critical leak
2. Tables with RLS enabled but zero policies AND direct anon grants → defense-in-depth issue
3. SECURITY DEFINER functions executable by anon → privilege escalation surface
4. Default privileges still grant CRUD on future tables → Supabase enforces revoke by Oct 30, 2026
5. Public storage buckets → asset leakage
6. Auth signups with autoconfirm enabled → signup abuse risk

Each finding includes the exact SQL needed to fix it. The skill never applies fixes automatically — it generates, you review, you run.

How to use

Quick audit (JSON to stdout)

SUPABASE_ACCESS_TOKEN=sbp_xxx \
  node scripts/audit.js <project-ref>

HTML report (recommended for sharing)

SUPABASE_ACCESS_TOKEN=sbp_xxx \
  node scripts/audit.js <project-ref> --html report.html

Open report.html in any browser. Self-contained (~25KB), Tailwind + Chart.js via CDN, copy-to-clipboard buttons on every fix.

Get a token

https://supabase.com/dashboard/account/tokens → New token. Read-only is enough for the audit; remediation needs no extra scope (you run the SQL yourself).

Remediation flow

1. Run the audit, get the HTML report.
2. Review each finding. Don't blindly apply fixes. Some "high" findings (e.g. is_admin() exposed to anon) are intentional API endpoints.
3. Click "Copy all SQL" at the bottom and paste into Dashboard → SQL Editor.
4. Run inside a transaction: BEGIN; ... ROLLBACK; first to verify, then BEGIN; ... COMMIT;.

Scope and limits

• Read-only by default. No fix is ever applied without you running the SQL.
• Cannot revoke supabase_admin default privileges via the Management API (Postgres permission limit). The audit reports this and points to the Dashboard toggle (Project Settings → Data API → "Automatically expose new tables" = OFF).
• No false-positive suppression for app APIs. A get_dashboard_stats() function intentionally exposed to anon will still appear as a high finding — exposed code paths are the surface area; you decide if intentional.
• Storage scan covers buckets only. Per-object RLS is not audited (would require iterating every object).

Why another Supabase scanner?

Most existing tools (SupaExplorer, AuditYourApp, Vibe App Scanner) are SaaS — your project ref + URL go to a third party. This skill runs locally with your own PAT. The only network calls are to api.supabase.com. Audit it: see scripts/audit.js, ~250 lines of plain Node.

License

MIT — see LICENSE.