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Supabase Extract Service Key

  • 322 installs
  • 60 repo stars
  • Updated January 31, 2026
  • yoanbernabeu/supabase-pentest-skills

supabase-extract-service-key is a Claude security skill that detects whether the Supabase service_role admin key has been accidentally exposed in client-side code for developers preventing P0 credential leaks before prod

About

supabase-extract-service-key is a Claude skill from yoanbernabeu/supabase-pentest-skills flagged as CRITICAL for detecting Supabase service_role key leaks in client-side code—a P0 severity issue. The skill scans JavaScript and TypeScript bundles for the admin credential that bypasses Row Level Security and must never ship in frontend assets. Findings write progressively to .sb-pentest-context.json and .sb-pentest-audit.log before and after each action so partial runs preserve evidence. Developers reach for supabase-extract-service-key during pre-deploy Supabase security reviews or CI secret-scanning gates. A positive detection should block release until the service_role key is rotated and removed from client code.

  • Detects exposed Supabase service_role admin key in client code
  • Critical pre-ship security check
  • Distinguishes service key from anon key exposure
  • Part of supabase-pentest-skills suite

Supabase Extract Service Key by the numbers

  • 322 all-time installs (skills.sh)
  • +13 installs in the week ending Jul 28, 2026 (Skillselion tracking)
  • Ranked #612 of 2,203 Security skills by installs in the Skillselion catalog
  • Data as of Aug 5, 2026 (Skillselion catalog sync)
npx skills add https://github.com/yoanbernabeu/supabase-pentest-skills --skill supabase-extract-service-key

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Listed on Skillselion
Installs322
repo stars60
Last updatedJanuary 31, 2026
Repositoryyoanbernabeu/supabase-pentest-skills

How do you detect Supabase service_role key leaks?

Detects whether the Supabase service_role key (an admin credential) has been accidentally exposed in client-side code, preventing a critical secret leak before shipping.

Who is it for?

Developers running pre-ship Supabase security audits who must confirm service_role keys never appear in client-side bundles.

Skip if: Backend-only services where service_role keys are correctly confined to server environment variables with no frontend exposure risk.

When should I use this skill?

A Supabase security review must confirm the service_role admin key is not exposed in client-side code before deploy.

What you get

P0 leak detection report, .sb-pentest-context.json entries, .sb-pentest-audit.log evidence trail, and remediation block recommendation.

  • P0 leak detection report
  • .sb-pentest-audit.log evidence trail

By the numbers

  • Classified as P0 severity for service_role key exposure
  • Writes progressively to .sb-pentest-context.json and .sb-pentest-audit.log

Files

SKILL.mdMarkdownGitHub ↗

Supabase Service Key Detection

🔴 CRITICAL: PROGRESSIVE FILE UPDATES REQUIRED

>

You MUST write to context files AS YOU GO, not just at the end.
- Write to .sb-pentest-context.json IMMEDIATELY after each discovery
- Log to .sb-pentest-audit.log BEFORE and AFTER each action
- DO NOT wait until the skill completes to update files
- If the skill crashes or is interrupted, all prior findings must already be saved

>

This is not optional. Failure to write progressively is a critical error.

This skill detects if the service_role key (admin key) is accidentally exposed in client-side code.

When to Use This Skill

  • As part of every security audit (this is critical)
  • When reviewing code before production deployment
  • After detecting Supabase usage to check for this common mistake

Prerequisites

  • Target application accessible
  • Supabase detection completed (auto-invokes if needed)

Why This Is Critical

The service_role key bypasses ALL Row Level Security (RLS) policies. If exposed:

ImpactDescription
🔴 Full DB AccessRead/write/delete all data in all tables
🔴 Auth BypassAccess all user data without authentication
🔴 Storage AccessRead/write all files in all buckets
🔴 User ImpersonationGenerate tokens for any user

This is a P0 (Critical) finding that requires immediate action.

Service Key vs Anon Key

AspectAnon KeyService Key
Role claim"role": "anon""role": "service_role"
RLS✅ Respects RLS❌ Bypasses RLS
Client-side✅ Expected❌ NEVER
Server-side✅ Can use✅ Should use

Detection Patterns

The skill searches for:

1. Key with service_role Claim

// Decoded JWT payload contains:
{
  "role": "service_role",  // ❌ CRITICAL if in client code
  "iss": "supabase",
  "ref": "abc123def"
}

2. Variable Names

// Common naming patterns
SUPABASE_SERVICE_KEY
SUPABASE_SERVICE_ROLE_KEY
SUPABASE_ADMIN_KEY
SUPABASE_SECRET_KEY
SERVICE_ROLE_KEY

3. Accidental Exposure

// Sometimes exposed alongside anon key
const keys = {
  anon: 'eyJ...',
  service: 'eyJ...'  // ❌ Should not be here
}

Usage

Basic Check

Check for service key leak on https://myapp.example.com

Deep Scan

Deep scan for service key exposure on https://myapp.example.com

Output Format

No Service Key Found (Good)

═══════════════════════════════════════════════════════════
 SERVICE KEY CHECK
═══════════════════════════════════════════════════════════

 Status: ✅ No service_role key detected in client code

 Scanned:
 ├── HTML source: Clean
 ├── JavaScript bundles: 5 files, 2.3MB analyzed
 ├── Inline scripts: 12 blocks checked
 └── Source maps: Not exposed (good)

 JWT Analysis:
 └── 1 key found, confirmed role=anon (safe)

 Result: PASS - No critical key exposure
═══════════════════════════════════════════════════════════

Service Key FOUND (Critical)

═══════════════════════════════════════════════════════════
 🔴 CRITICAL: SERVICE KEY EXPOSED
═══════════════════════════════════════════════════════════

 Severity: P0 - CRITICAL
 Status: ❌ service_role key found in client-side code!

 ⚠️  IMMEDIATE ACTION REQUIRED ⚠️

 Exposed Key:
 eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJzdXBh
 YmFzZSIsInJlZiI6ImFiYzEyM2RlZiIsInJvbGUiOiJzZXJ2aWNlX3
 JvbGUiLCJpYXQiOjE2NDAwMDAwMDAsImV4cCI6MTk1NTM2MDAwMH0
 .xxxxxxxxxxxxx

 Location:
 └── /static/js/admin.chunk.js (line 89)
     const SUPABASE_KEY = 'eyJhbG...'  // Used in createClient()

 Decoded Payload:
 ├── role: service_role ← CRITICAL
 ├── ref: abc123def
 └── exp: 2031-12-20

 Impact Assessment:
 ├── 🔴 Full database access possible
 ├── 🔴 All RLS policies bypassed
 ├── 🔴 All user data exposed
 └── 🔴 All storage buckets accessible

 ═══════════════════════════════════════════════════════════
 IMMEDIATE REMEDIATION STEPS
 ═══════════════════════════════════════════════════════════

 1. ROTATE THE KEY NOW
    → Supabase Dashboard > Settings > API > Regenerate service_role key

 2. REMOVE FROM CLIENT CODE
    → Delete the key from your source code
    → Redeploy your application

 3. AUDIT FOR ABUSE
    → Check Supabase logs for unauthorized access
    → Review database for unexpected changes

 4. USE EDGE FUNCTIONS
    → Move privileged operations to Edge Functions
    → Client calls Edge Function, which uses service key server-side

 Documentation:
 → https://supabase.com/docs/guides/api/api-keys
 → https://supabase.com/docs/guides/functions

═══════════════════════════════════════════════════════════

Context Output

Saved to .sb-pentest-context.json:

{
  "findings": [
    {
      "id": "SERVICE_KEY_EXPOSED",
      "severity": "P0",
      "title": "Service Role Key Exposed in Client Code",
      "description": "The service_role key was found in client-side JavaScript",
      "location": {
        "file": "/static/js/admin.chunk.js",
        "line": 89
      },
      "evidence": {
        "key_prefix": "eyJhbGciOiJIUzI1NiI...",
        "role": "service_role",
        "project_ref": "abc123def"
      },
      "remediation": {
        "immediate": "Rotate key in Supabase Dashboard",
        "long_term": "Move to Edge Functions",
        "docs": "https://supabase.com/docs/guides/api/api-keys"
      }
    }
  ],
  "supabase": {
    "service_key_exposed": true,
    "service_key_location": "/static/js/admin.chunk.js:89"
  }
}

Source Maps Check

The skill also checks for exposed source maps that might reveal keys:

Source Maps Analysis:
├── main.js.map: ❌ Exposed (may contain secrets)
├── vendor.js.map: ❌ Exposed
└── Recommendation: Disable source maps in production

To check source maps content:
→ Add .map to JS URLs: /static/js/main.js.map

Common Causes

CauseSolution
Wrong env variableUse NEXT_PUBLIC_ only for anon key
Copy-paste errorDouble-check which key you're using
Debug code left inRemove before production build
Misconfigured bundlerEnsure service key env vars are not included

Remediation Code Examples

Before (Wrong)

// ❌ WRONG - Service key in client
import { createClient } from '@supabase/supabase-js'

const supabase = createClient(
  process.env.NEXT_PUBLIC_SUPABASE_URL,
  process.env.NEXT_PUBLIC_SUPABASE_SERVICE_KEY  // ❌ NEVER DO THIS
)

After (Correct)

// ✅ CORRECT - Only anon key in client
import { createClient } from '@supabase/supabase-js'

const supabase = createClient(
  process.env.NEXT_PUBLIC_SUPABASE_URL,
  process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY  // ✅ Safe for client
)

// For privileged operations, call an Edge Function:
const { data } = await supabase.functions.invoke('admin-action', {
  body: { action: 'delete-user', userId: '123' }
})

Edge Function (Server-Side)

// supabase/functions/admin-action/index.ts
import { createClient } from '@supabase/supabase-js'

Deno.serve(async (req) => {
  // ✅ Service key only on server
  const supabase = createClient(
    Deno.env.get('SUPABASE_URL'),
    Deno.env.get('SUPABASE_SERVICE_ROLE_KEY')  // ✅ Safe on server
  )

  // Perform privileged operation
  // ...
})

MANDATORY: Progressive Context File Updates

⚠️ This skill MUST update tracking files PROGRESSIVELY during execution, NOT just at the end.

Critical Rule: Write As You Go

DO NOT batch all writes at the end. Instead:

1. Before starting any action → Log the action to .sb-pentest-audit.log 2. After each discovery → Immediately update .sb-pentest-context.json 3. After each significant step → Log completion to .sb-pentest-audit.log

This ensures that if the skill is interrupted, crashes, or times out, all findings up to that point are preserved.

Required Actions (Progressive)

1. Update `.sb-pentest-context.json` with findings:

   {
     "supabase": {
       "service_key_exposed": true/false,
       "service_key_location": "path:line"
     },
     "findings": [
       {
         "id": "SERVICE_KEY_EXPOSED",
         "severity": "P0",
         "title": "Service Role Key Exposed",
         ...
       }
     ]
   }

2. Log to `.sb-pentest-audit.log`:

   [TIMESTAMP] [supabase-extract-service-key] [START] Checking for service key exposure
   [TIMESTAMP] [supabase-extract-service-key] [CRITICAL] Service key EXPOSED at path:line
   [TIMESTAMP] [supabase-extract-service-key] [CONTEXT_UPDATED] .sb-pentest-context.json updated

3. If files don't exist, create them before writing.

FAILURE TO UPDATE CONTEXT FILES IS NOT ACCEPTABLE.

MANDATORY: Evidence Collection

📁 Evidence Directory: .sb-pentest-evidence/02-extraction/service-key-exposure/

Evidence Files to Create (if service key found)

FileContent
service-key-exposure/location.txtFile path and line number
service-key-exposure/decoded-payload.jsonDecoded JWT proving it's service_role
service-key-exposure/code-snippet.txtCode context (redacted)

Evidence Format (P0 Finding)

{
  "evidence_id": "EXT-SVC-001",
  "timestamp": "2025-01-31T10:10:00Z",
  "category": "extraction",
  "type": "service_key_exposure",
  "severity": "P0",
  "finding_id": "P0-001",

  "key_data": {
    "key_prefix": "eyJhbGciOiJIUzI1NiI...",
    "key_suffix": "...xxxx",
    "role": "service_role"
  },

  "decoded_payload": {
    "iss": "supabase",
    "ref": "abc123def",
    "role": "service_role",
    "iat": "2021-12-20T00:00:00Z",
    "exp": "2031-12-20T00:00:00Z"
  },

  "location": {
    "file": "/static/js/admin.chunk.js",
    "line": 89,
    "context": "const SUPABASE_KEY = 'eyJhbG...' // [REDACTED]"
  },

  "impact": {
    "rls_bypass": true,
    "full_db_access": true,
    "auth_users_access": true,
    "storage_access": true
  },

  "curl_command": "curl -X GET 'https://abc123def.supabase.co/rest/v1/users' -H 'apikey: [SERVICE_KEY]' -H 'Authorization: Bearer [SERVICE_KEY]'"
}

Add to timeline.md (P0)

## [TIMESTAMP] - 🔴 P0 CRITICAL: Service Role Key Exposed
- Service role key found in client-side code
- Location: [file]:[line]
- Impact: Full database access, RLS bypass
- Evidence: `02-extraction/service-key-exposure/`
- **IMMEDIATE ACTION REQUIRED**

Related Skills

  • supabase-extract-anon-key — Extract the (expected) anon key
  • supabase-audit-tables-read — Test what data is accessible
  • supabase-report — Generate full report including this finding

Related skills

FAQ

Why is supabase-extract-service-key P0 severity?

supabase-extract-service-key flags P0 severity because a service_role key in client-side code grants admin access that bypasses Row Level Security. Exposed service_role credentials require immediate rotation and deploy blocking.

What happens when supabase-extract-service-key finds a leak?

supabase-extract-service-key logs the finding to .sb-pentest-context.json and .sb-pentest-audit.log progressively. Developers must rotate the service_role key, remove it from client bundles, and block release until remediation completes.

Securitysecretsauditappsec

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