supabase-audit-buckets-read

Imported from yoanbernabeu/supabase-pentest-skills (skills/audit-storage/supabase-audit-buckets-read/SKILL.md) via skills.sh. Install upstream with npx skills add yoanbernabeu/supabase-pentest-skills --skill supabase-audit-buckets-read. Copyright stays with the author.

Bucket File Access Test

🔴 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 bucket tested
• Log to .sb-pentest-audit.log BEFORE and AFTER each file access test
• 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 tests actual file access in storage buckets to verify permissions.

When to Use This Skill

• After listing buckets, to verify actual access
• To test storage RLS policy effectiveness
• To check for sensitive file exposure
• To document what files are accessible

Prerequisites

• Buckets listed (auto-invokes if needed)
• Anon key available

How It Works

The skill attempts to:

1. List files in each bucket
2. Read file metadata
3. Download sample files (for content type verification)
4. Check public URL access

Important: This is READ-ONLY. No files are modified or deleted.

Test Approach

Usage

Basic Read Test

Test read access on storage buckets

Specific Bucket

Test file access on the documents bucket

List Only (No Download)

List accessible files without downloading content

Output Format

═══════════════════════════════════════════════════════════
 BUCKET FILE ACCESS TEST
═══════════════════════════════════════════════════════════

 Project: abc123def.supabase.co
 Buckets Tested: 5

 ─────────────────────────────────────────────────────────
 avatars (Public Bucket)
 ─────────────────────────────────────────────────────────

 Status: ✅ Expected Access
 Files Found: 1,247

 Sample Files:
 ├── user-550e8400.jpg (45KB) - Public URL works
 ├── user-6ba7b810.png (32KB) - Public URL works
 └── default.png (12KB) - Public URL works

 Access Methods:
 ├── Public URL: ✅ Accessible
 ├── API Listing: ✅ Works
 └── Metadata: ✅ Visible

 Assessment: Expected behavior for avatar storage.

 ─────────────────────────────────────────────────────────
 documents (Private Bucket)
 ─────────────────────────────────────────────────────────

 Status: ✅ PROPERLY PROTECTED
 Files Found: 0 (via anon key)

 Access Methods:
 ├── Public URL: ❌ 403 Forbidden (correct)
 ├── API Listing: ❌ Empty result (RLS working)
 └── Metadata: ❌ Not accessible (correct)

 Assessment: RLS policies working correctly.

 ─────────────────────────────────────────────────────────
 uploads (Public Bucket)
 ─────────────────────────────────────────────────────────

 Status: 🟠 P1 - SENSITIVE FILES EXPOSED
 Files Found: 3,891

 Sensitive Files Detected:
 ├── 🔴 invoice-2025-001.pdf - Contains financial data
 ├── 🔴 contract-signed.pdf - Legal document
 ├── 🔴 id-verification.jpg - Personal ID photo!
 ├── ⚠️ database-export.csv - Possible data export
 └── ⚠️ config.json - Configuration file

 File Types Distribution:
 ├── PDF: 1,234 (31%)
 ├── Images: 2,100 (54%)
 ├── Documents: 450 (12%)
 └── Other: 107 (3%)

 Assessment: Bucket contains sensitive files that should not be public!

 ─────────────────────────────────────────────────────────
 backups (Public - CRITICAL)
 ─────────────────────────────────────────────────────────

 Status: 🔴 P0 - CRITICAL DATA EXPOSURE
 Files Found: 45

 Exposed Files:
 ├── 🔴 db-backup-2025-01-30.sql (125MB) - DATABASE BACKUP!
 ├── 🔴 db-backup-2025-01-29.sql (124MB) - DATABASE BACKUP!
 ├── 🔴 users-export.csv (2.3MB) - USER DATA EXPORT!
 ├── 🔴 secrets.env (1KB) - ENVIRONMENT SECRETS!
 └── 🔴 .env.production (1KB) - PRODUCTION SECRETS!

 Sample Content (secrets.env):
 ┌─────────────────────────────────────────────────────────┐
 │ STRIPE_SECRET_KEY=sk_live_xxxxxxxxxxxx                 │
 │ DATABASE_URL=postgresql://postgres:xxx@...             │
 │ JWT_SECRET=super-secret-jwt-key                        │
 └─────────────────────────────────────────────────────────┘

 ⚠️ IMMEDIATE ACTION REQUIRED:
 1. Make bucket private NOW
 2. Rotate ALL exposed secrets
 3. Delete backup files from public access
 4. Audit for unauthorized access in logs

 ─────────────────────────────────────────────────────────
 temp (Private Bucket)
 ─────────────────────────────────────────────────────────

 Status: ✅ PROPERLY PROTECTED
 Files Found: 0 (via anon key)
 Assessment: Access correctly restricted.

 ─────────────────────────────────────────────────────────
 Summary
 ─────────────────────────────────────────────────────────

 P0 Critical: 1 bucket (backups - DB dumps & secrets exposed)
 P1 High: 1 bucket (uploads - sensitive documents in public bucket)
 Protected: 2 buckets (documents, temp)
 Expected: 1 bucket (avatars)

 Total Files Accessible: 5,183
 Sensitive Files Exposed: 52
 Secret Files Exposed: 3

 Immediate Actions:
 1. 🔴 DELETE or make private 'backups' bucket
 2. 🔴 Rotate Stripe key, DB password, JWT secret
 3. 🟠 Move sensitive files from 'uploads' to private bucket
 4. Review all 52 sensitive files for exposure impact

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

Sensitive File Detection

The skill identifies sensitive files by:

Filename Patterns

Content Detection

For accessible files, the skill samples content for:

• API keys (patterns like sk_live_, pk_test_)
• Database credentials
• JWT secrets
• Personal information patterns

Context Output

{
  "storage_access": {
    "timestamp": "2025-01-31T11:30:00Z",
    "buckets_tested": 5,
    "findings": [
      {
        "bucket": "backups",
        "severity": "P0",
        "public": true,
        "files_exposed": 45,
        "sensitive_files": [
          {
            "path": "db-backup-2025-01-30.sql",
            "size": 131072000,
            "type": "database_backup",
            "risk": "Full database accessible"
          },
          {
            "path": "secrets.env",
            "size": 1024,
            "type": "secrets",
            "exposed_secrets": ["STRIPE_SECRET_KEY", "DATABASE_URL", "JWT_SECRET"]
          }
        ]
      }
    ],
    "summary": {
      "total_files_accessible": 5183,
      "sensitive_files": 52,
      "secret_files": 3
    }
  }
}

Remediation Steps

For Exposed Secrets

# 1. Rotate Stripe keys
# Stripe Dashboard → Developers → API Keys → Roll Keys

# 2. Change database password
# Supabase Dashboard → Settings → Database → Reset Password

# 3. Regenerate JWT secret
# Supabase Dashboard → Settings → API → Regenerate JWT Secret

# 4. Update application environment variables
# Redeploy with new secrets

For Public Bucket Fix

-- Make bucket private
UPDATE storage.buckets
SET public = false
WHERE name = 'backups';

-- Delete sensitive files or move to secure location
DELETE FROM storage.objects
WHERE bucket_id = 'backups';

For Upload Bucket

-- Add RLS to restrict access
CREATE POLICY "Users access own uploads"
  ON storage.objects FOR ALL
  USING (
    bucket_id = 'uploads'
    AND auth.uid()::text = (storage.foldername(name))[1]
  );

Common Issues

❌ Problem: Cannot list files in private bucket ✅ Solution: This is correct behavior. RLS is working.

❌ Problem: Large number of files to scan ✅ Solution: Use sampling mode for large buckets.

❌ Problem: File download fails ✅ Solution: May be RLS restriction or network issue.

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 testing each bucket → Log the action to .sb-pentest-audit.log
2. After each sensitive file found → Immediately update .sb-pentest-context.json
3. After each bucket completed → Log the summary

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 results:

   {
     "storage_access": {
       "timestamp": "...",
       "buckets_tested": 5,
       "findings": [ ... ],
       "summary": { "total_files_accessible": 5183, ... }
     }
   }

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

   [TIMESTAMP] [supabase-audit-buckets-read] [START] Testing bucket file access
   [TIMESTAMP] [supabase-audit-buckets-read] [FINDING] P0: backups bucket has exposed secrets
   [TIMESTAMP] [supabase-audit-buckets-read] [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/04-storage-audit/buckets/

Evidence Files to Create

Evidence Format (Sensitive Files Exposed)

{
  "evidence_id": "STG-READ-001",
  "timestamp": "2025-01-31T10:40:00Z",
  "category": "storage-audit",
  "type": "file_access",
  "severity": "P0",

  "bucket": "backups",
  "public": true,

  "files_found": 45,
  "sensitive_files": [
    {
      "path": "db-backup-2025-01-30.sql",
      "size": 131072000,
      "type": "database_backup",
      "public_url": "https://abc123def.supabase.co/storage/v1/object/public/backups/db-backup-2025-01-30.sql",
      "curl_command": "curl -o backup.sql 'https://abc123def.supabase.co/storage/v1/object/public/backups/db-backup-2025-01-30.sql'"
    },
    {
      "path": "secrets.env",
      "size": 1024,
      "type": "secrets_file",
      "content_sample": "STRIPE_SECRET_KEY=sk_live_[REDACTED]\nDATABASE_URL=postgresql://[REDACTED]",
      "exposed_secrets": ["STRIPE_SECRET_KEY", "DATABASE_URL", "JWT_SECRET"]
    }
  ],

  "impact": {
    "data_breach": true,
    "secrets_exposed": true,
    "affected_records": "All database records",
    "credentials_to_rotate": ["Stripe API key", "Database password", "JWT secret"]
  }
}

Add to curl-commands.sh

# === STORAGE FILE ACCESS TESTS ===
# List files in backups bucket
curl -s "$SUPABASE_URL/storage/v1/object/list/backups" \
  -H "apikey: $ANON_KEY"

# Direct access to public file (P0 if accessible)
curl -I "https://abc123def.supabase.co/storage/v1/object/public/backups/secrets.env"

# Download exposed backup (for evidence - be careful with size)
# curl -o evidence-backup-sample.sql "https://abc123def.supabase.co/storage/v1/object/public/backups/db-backup-2025-01-30.sql" | head -1000

Related Skills

• supabase-audit-buckets-list — List buckets first
• supabase-audit-buckets-public — Focus on public access issues
• supabase-report — Generate full report