supabase-extract-service-key

Imported from yoanbernabeu/supabase-pentest-skills (skills/extraction/supabase-extract-service-key/SKILL.md) via skills.sh. Install upstream with npx skills add yoanbernabeu/supabase-pentest-skills --skill supabase-extract-service-key. Copyright stays with the author.

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:

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

Service Key vs Anon Key

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

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)

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