security-audit

Security Audit Skill

Overview

This skill performs systematic security audits of Move contracts using a comprehensive checklist. Every item must pass before deployment.

Critical: Security is non-negotiable. User funds depend on correct implementation.

Core Workflow

Step 1: Run Security Checklist

Review ALL categories in order:

1. Access Control - Who can call functions?
2. Input Validation - Are inputs checked?
3. Object Safety - Object model used correctly?
4. Reference Safety - No dangerous references exposed?
5. Arithmetic Safety - Overflow/underflow prevented?
6. Generic Type Safety - Phantom types used correctly?
7. Testing - 100% coverage achieved?

Step 2: Access Control Audit

Verify:

• All entry functions verify signer authority
• Object ownership checked with object::owner()
• Admin functions check caller is admin
• Function visibility uses least-privilege
• No public functions modify state without checks

Check for:

// ✅ CORRECT: Signer verification
public entry fun update_config(admin: &signer, value: u64) acquires Config {
    let config = borrow_global<Config>(@my_addr);
    assert!(signer::address_of(admin) == config.admin, E_NOT_ADMIN);
    // Safe to proceed
}

// ❌ WRONG: No verification
public entry fun update_config(admin: &signer, value: u64) acquires Config {
    let config = borrow_global_mut<Config>(@my_addr);
    config.value = value; // Anyone can call!
}

For objects:

// ✅ CORRECT: Ownership verification
public entry fun transfer_item(
    owner: &signer,
    item: Object<Item>,
    to: address
) acquires Item {
    assert!(object::owner(item) == signer::address_of(owner), E_NOT_OWNER);
    // Safe to transfer
}

// ❌ WRONG: No ownership check
public entry fun transfer_item(
    owner: &signer,
    item: Object<Item>,
    to: address
) acquires Item {
    // Anyone can transfer any item!
}

Step 3: Input Validation Audit