---

name: security-scan description: Audits code security against OWASP Top 10. Validates user ID from session, detects sensitive data leaks, verifies Zod validation. HAS VETO POWER - blocks insecure code. allowed-tools: Read, Grep, Glob, Bash

Security Scan - Security Audit System

VETO POWER

WARNING: This skill HAS VETO POWER. If critical vulnerability detected, MUST:

1. STOP implementation
2. REPORT vulnerability
3. REQUIRE fix before proceeding

---

Purpose

This skill audits code security:

• Validates user ID comes from session (NEVER from request)
• Detects sensitive data being sent to frontend
• Verifies Zod validation on all routes
• Audits against OWASP Top 10
• Blocks commits with critical vulnerabilities

---

Critical Security Rules

1. USER ID ALWAYS FROM SESSION

NEVER trust user ID from frontend. ALWAYS extract from ctx.session.userId or ctx.user._id.

// WRONG - VULNERABLE (IMMEDIATE VETO)
async function getData({ userId }: { userId: string }) {
	return db.find({ userId }); // userId can be manipulated!
}

// CORRECT
async function getData({ ctx }: { ctx: Context }) {
	const userId = ctx.user._id; // Always from session
	return db.find({ userId });
}

2. SENSITIVE DATA NEVER TO FRONTEND

NEVER send to frontend:

• Passwords (even hashed)
• API tokens
• Secret keys
• Other users' data
• Stack traces in production

// WRONG - DATA LEAK (IMMEDIATE VETO)
return {
	user: await UserModel.findById(id), // Includes passwordHash!
};

// CORRECT
return {
	user: user.toPublic(), // Sanitization method
};

3. ZOD VALIDATION REQUIRED

EVERY tRPC route MUST have .input(z.object({...})). Unvalidated inputs are attack vectors.

// WRONG - NO VALIDATION (IMMEDIATE VETO)
.mutation(async ({ input }) => {
  await db.create(input); // input can have anything!
})

// CORRECT
.input(createSchema) // Zod schema
.mutation(async ({ input }) => {
  await db.create(input); // input is validated
})

---

OWASP Top 10 Checklist

A01: Broken Access Control

• [ ] All protected routes use protectedProcedure?
• [ ] User ID from session, not input?
• [ ] Resources filtered by user/tenant?

A02: Cryptographic Failures

• [ ] Passwords hashed with bcrypt (salt >= 10)?
• [ ] Tokens generated with crypto.randomBytes?
• [ ] Cookies with HttpOnly, Secure, SameSite?
• [ ] No secrets in code (use env vars)?

A03: Injection

• [ ] Queries use Mongoose (prevents NoSQL injection)?
• [ ] Inputs validated with Zod?
• [ ] No string concatenation in queries?

A07: Authentication Failures

• [ ] Passwords with minimum requirements?
• [ ] Brute force protection?
• [ ] Sessions invalidated on logout?
• [ ] Tokens with expiration?

---

Detection Patterns

Detect User ID from Input (VETO)

grep -r "input\.userId\|input\.user_id\|{ userId }" server/ --include="*.ts"

Detect Password Return (VETO)

grep -r "passwordHash\|password:" server/ --include="*.ts"

Detect Route Without Validation (VETO)

grep -A5 "Procedure\." server/ --include="*.ts" | grep -v ".input("

---

Output Format

Approved

## SECURITY SCAN - APPROVED

### Scope

- **Files:** X
- **Routes:** Y

### Checks

- [x] User ID always from session
- [x] No sensitive data in response
- [x] All routes with Zod validation
- [x] OWASP Top 10 OK

**STATUS: APPROVED**

Vetoed

## SECURITY SCAN - VETOED

### CRITICAL VULNERABILITY

**Type:** User ID from Input
**File:** `server/routers/example.ts:45`
**Risk:** Any user can access other users' data

**Fix:** Use `ctx.user._id` instead of `input.userId`

**STATUS: VETOED** - Fix before proceeding

---

VETO Rules

IMMEDIATE VETO

1. User ID from input/request body
2. Password returned in response
3. API tokens exposed
4. Protected route without protectedProcedure
5. Query without user/tenant filter

VETO BEFORE MERGE

1. Route without Zod validation
2. Unsanitized sensitive data
3. bun audit (or npm audit) with critical vulnerabilities

---

Progressive Disclosure

For detailed information, see:

• reference/owasp-top-10.md - Complete OWASP Top 10 checklist with examples
• scripts/scan.py - Automated security scanner

Quick Scan

python .claude/skills/security-scan/scripts/scan.py server/

---

Version

• v2.1.0 - Added progressive disclosure with reference files and scan script
• v2.0.0 - Generic template