
supabase-audit-auth-signup
Test if user signup is open and identify potential abuse vectors in the registration process.
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Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/yoanbernabeu/supabase-pentest-skills --skill supabase-audit-auth-signup- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads supabase-audit-auth-signup automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
SKILL.md
The instructions your agent reads when the skill is triggered.
Signup Flow Audit
🔴 CRITICAL: PROGRESSIVE FILE UPDATES REQUIRED
You MUST write to context files AS YOU GO, not just at the end.
- Write to
.sb-pentest-context.jsonIMMEDIATELY after each test completed- Log to
.sb-pentest-audit.logBEFORE and AFTER each 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 the user registration flow for security issues and misconfigurations.
When to Use This Skill
- To verify if signup is appropriately restricted
- To test for signup abuse vectors
- To check rate limiting on registration
- As part of authentication security audit
Prerequisites
- Supabase URL and anon key available
- Auth config audit completed (recommended)
Why Signup Security Matters
Open signup can lead to:
| Risk | Description |
|---|---|
| Spam accounts | Bots creating fake accounts |
| Resource abuse | Free tier exploitation |
| Email spam | Using your service to send emails |
| Data pollution | Fake data in your database |
| Attack surface | More accounts = more attack vectors |
Tests Performed
| Test | Purpose |
|---|---|
| Signup availability | Is registration open? |
| Email validation | Does it accept invalid emails? |
| Rate limiting | Can we create many accounts? |
| Disposable emails | Are temp emails blocked? |
| Password policy | What passwords are accepted? |
| Response information | What info is leaked? |
Usage
Basic Signup Test
Test signup security on my Supabase project
Check Specific Aspects
Test if disposable emails are blocked for signup
Output Format
═══════════════════════════════════════════════════════════
SIGNUP FLOW AUDIT
═══════════════════════════════════════════════════════════
Project: abc123def.supabase.co
Endpoint: /auth/v1/signup
─────────────────────────────────────────────────────────
Signup Availability
─────────────────────────────────────────────────────────
Status: ✅ OPEN (Anyone can register)
Test Result:
POST /auth/v1/signup
Body: {"email": "test-xxxxx@example.com", "password": "TestPass123!"}
Response: 200 OK - Account created
Assessment: Signup is publicly available.
Review if this is intended.
─────────────────────────────────────────────────────────
Email Validation
─────────────────────────────────────────────────────────
Valid email formats:
├── user@domain.com: ✅ Accepted (expected)
├── user+tag@domain.com: ✅ Accepted (expected)
└── user@subdomain.domain.com: ✅ Accepted (expected)
Invalid email formats:
├── user@: ❌ Rejected (good)
├── @domain.com: ❌ Rejected (good)
├── user@.com: ❌ Rejected (good)
└── not-an-email: ❌ Rejected (good)
Disposable Email Test:
├── user@mailinator.com: ✅ Accepted ← 🟠 P2
├── user@tempmail.com: ✅ Accepted ← 🟠 P2
└── user@guerrillamail.com: ✅ Accepted ← 🟠 P2
Finding: Disposable emails are not blocked.
Risk: Users can create throwaway accounts.
Recommendation: Consider using an email validation
service or blocklist in your application logic.
─────────────────────────────────────────────────────────
Password Policy
─────────────────────────────────────────────────────────
Minimum Length Test:
├── "12345" (5 chars): ❌ Rejected
├── "123456" (6 chars): ✅ Accepted ← P2 Short
└── "1234567890" (10 chars): ✅ Accepted
Current Policy: Minimum 6 characters
Weak Password Test:
├── "password": ✅ Accepted ← 🟠 P2
├── "123456": ✅ Accepted ← 🟠 P2
├── "qwerty123": ✅ Accepted ← 🟠 P2
└── "letmein": ✅ Accepted ← 🟠 P2
Finding: Common weak passwords are accepted.
Recommendation:
1. Increase minimum length to 8+ characters
2. Consider password strength requirements
3. Check against common password lists
─────────────────────────────────────────────────────────
Rate Limiting
─────────────────────────────────────────────────────────
Signup Rate Test (same IP):
├── Request 1: ✅ 200 OK
├── Request 2: ✅ 200 OK
├── Request 3: ✅ 200 OK
├── Request 4: ❌ 429 Too Many Requests
└── Retry-After: 3600 seconds
Rate Limit: 3 signups/hour per IP
Assessment: ✅ Rate limiting is active (good)
─────────────────────────────────────────────────────────
Information Disclosure
─────────────────────────────────────────────────────────
Existing Email Test:
POST /auth/v1/signup (with existing email)
Response: "User already registered"
Finding: 🟠 P2 - Response reveals email existence
This allows:
├── Email enumeration attacks
├── Knowing if someone has an account
└── Targeted phishing attempts
Recommendation: Use generic message like
"Check your email to continue" for both new
and existing accounts.
─────────────────────────────────────────────────────────
Email Confirmation
─────────────────────────────────────────────────────────
Status: ❌ NOT REQUIRED (confirmed in auth-config)
Test: Created account and checked session
Result: User immediately authenticated without
email confirmation.
─────────────────────────────────────────────────────────
Summary
─────────────────────────────────────────────────────────
Signup: Open to public
Rate Limiting: ✅ Active (3/hour)
Email Confirmation: ❌ Not required
Findings:
├── P1: Email confirmation disabled
├── P2: Disposable emails accepted
├── P2: Weak passwords accepted
└── P2: Email enumeration possible
Security Score: 5/10
Priority Actions:
1. Enable email confirmation
2. Strengthen password policy
3. Consider disposable email blocking
4. Use generic error messages
═══════════════════════════════════════════════════════════
Test Details
Disposable Email Detection
Common disposable email domains tested:
- mailinator.com
- tempmail.com
- guerrillamail.com
- 10minutemail.com
- throwaway.email
Weak Password List
Common passwords tested:
- password, password123
- 123456, 12345678
- qwerty, qwerty123
- letmein, welcome
- admin, administrator
Rate Limit Testing
Attempt 1: 200 OK
Attempt 2: 200 OK
Attempt 3: 200 OK
Attempt 4: 429 Too Many Requests
Context Output
{
"signup_audit": {
"timestamp": "2025-01-31T13:00:00Z",
"signup_open": true,
"rate_limit": {
"enabled": true,
"limit": 3,
"period": "hour"
},
"email_validation": {
"basic_validation": true,
"disposable_blocked": false
},
"password_policy": {
"min_length": 6,
"weak_passwords_blocked": false
},
"information_disclosure": {
"email_enumeration": true
},
"findings": [
{
"severity": "P1",
"issue": "Email confirmation disabled"
},
{
"severity": "P2",
"issue": "Disposable emails accepted"
},
{
"severity": "P2",
"issue": "Weak passwords accepted"
},
{
"severity": "P2",
"issue": "Email enumeration possible"
}
]
}
}
Remediation Examples
Block Disposable Emails
// In your signup handler or Edge Function
import { isDisposable } from 'email-validator-package';
if (isDisposable(email)) {
throw new Error('Please use a permanent email address');
}
Strengthen Password Requirements
// Custom password validation
function validatePassword(password: string): boolean {
if (password.length < 8) return false;
if (!/[A-Z]/.test(password)) return false;
if (!/[a-z]/.test(password)) return false;
if (!/[0-9]/.test(password)) return false;
return true;
}
Prevent Email Enumeration
// Always return same message
async function signup(email, password) {
try {
await supabase.auth.signUp({ email, password });
} catch (error) {
// Don't reveal if email exists
}
return { message: 'Check your email to continue' };
}
Restrict Signup
If signup should be invite-only:
// Use admin API to invite users
const { data, error } = await supabaseAdmin.auth.admin.inviteUserByEmail(
'user@example.com'
);
// Or disable signup in dashboard and use:
const { data, error } = await supabaseAdmin.auth.admin.createUser({
email: 'user@example.com',
email_confirm: true
});
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:
- Before each signup test → Log the action to
.sb-pentest-audit.log - After each vulnerability found → Immediately update
.sb-pentest-context.json - After rate limit tests → Log the results immediately
This ensures that if the skill is interrupted, crashes, or times out, all findings up to that point are preserved.
Required Actions (Progressive)
-
Update
.sb-pentest-context.jsonwith results:{ "signup_audit": { "timestamp": "...", "signup_open": true, "rate_limit": { ... }, "findings": [ ... ] } } -
Log to
.sb-pentest-audit.log:[TIMESTAMP] [supabase-audit-auth-signup] [START] Testing signup security [TIMESTAMP] [supabase-audit-auth-signup] [FINDING] P2: Weak passwords accepted [TIMESTAMP] [supabase-audit-auth-signup] [CONTEXT_UPDATED] .sb-pentest-context.json updated -
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/05-auth-audit/signup-tests/
Evidence Files to Create
| File | Content |
|---|---|
signup-tests/open-signup.json | Signup availability test |
signup-tests/weak-password.json | Weak password acceptance test |
signup-tests/disposable-email.json | Disposable email test |
signup-tests/rate-limit.json | Rate limiting test |
Evidence Format
{
"evidence_id": "AUTH-SIGNUP-001",
"timestamp": "2025-01-31T10:55:00Z",
"category": "auth-audit",
"type": "signup_test",
"tests": [
{
"test_name": "weak_password_acceptance",
"severity": "P2",
"request": {
"method": "POST",
"url": "https://abc123def.supabase.co/auth/v1/signup",
"body": {"email": "test@example.com", "password": "123456"},
"curl_command": "curl -X POST '$URL/auth/v1/signup' -H 'apikey: $ANON_KEY' -H 'Content-Type: application/json' -d '{\"email\": \"test@example.com\", \"password\": \"123456\"}'"
},
"response": {
"status": 200,
"message": "User created"
},
"result": "VULNERABLE",
"impact": "Weak passwords (6 chars) accepted"
},
{
"test_name": "disposable_email",
"severity": "P2",
"request": {
"body": {"email": "test@mailinator.com", "password": "Test123456!"}
},
"response": {
"status": 200,
"message": "User created"
},
"result": "VULNERABLE",
"impact": "Disposable emails not blocked"
}
]
}
Related Skills
supabase-audit-auth-config— Full auth configurationsupabase-audit-auth-users— User enumeration testingsupabase-audit-rls— Protect user data with RLS
FAQ
What does the supabase-audit-auth-signup skill do?
Test if user signup is open and identify potential abuse vectors in the registration process.
How do I install supabase-audit-auth-signup?
Run npx skills add https://github.com/yoanbernabeu/supabase-pentest-skills --skill supabase-audit-auth-signup in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/supabase-audit-auth-signup/ (personal) or .claude/skills/supabase-audit-auth-signup/ (project).
Which AI agents can use supabase-audit-auth-signup?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is supabase-audit-auth-signup safe to install?
No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.
Who maintains supabase-audit-auth-signup?
It is published by yoanbernabeu in yoanbernabeu/supabase-pentest-skills. It has 474 recorded installs.
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