impersonator/docs/06-security.md

Security Guide

Comprehensive security documentation for the Impersonator Smart Wallet system.

Security Overview

The Impersonator system implements multiple layers of security to protect user data and prevent attacks:

1. Encryption Layer - Encrypted storage for sensitive data
2. Validation Layer - Comprehensive input validation
3. Access Control Layer - Owner verification and authorization
4. Rate Limiting Layer - DoS attack prevention
5. Replay Protection - Message and transaction replay prevention

Security Features

1. Encrypted Storage

All sensitive data is encrypted before storage using AES-GCM encryption.

Implementation:

• AES-GCM encryption with 256-bit keys
• PBKDF2 key derivation (100,000 iterations)
• Session-based encryption keys
• Automatic encryption/decryption

Usage:

import { SecureStorage } from "@/utils/encryption";

const storage = new SecureStorage();
await storage.setItem("wallets", JSON.stringify(wallets));

What's Encrypted:

• Wallet configurations
• Transaction data
• Owner information
• Threshold settings

2. Input Validation

All user inputs are validated before processing.

Address Validation:

import { validateAddress } from "@/utils/security";

const validation = validateAddress(address);
if (!validation.valid) {
  // Handle invalid address
}

Transaction Validation:

import { validateTransactionRequest } from "@/utils/security";

const validation = validateTransactionRequest(tx);
if (!validation.valid) {
  console.error(validation.errors);
}

Validation Checks:

• Address format and checksum
• Network ID support
• Transaction data format
• Value limits (max 1M ETH)
• Gas limit bounds (21k - 10M)
• Data size limits (max 10KB)

3. Access Control

All sensitive operations require authorization.

Owner Verification:

// Before adding owner
const isOwner = activeWallet.owners.some(
  o => o.toLowerCase() === callerAddress.toLowerCase()
);
if (!isOwner) {
  throw new Error("Unauthorized");
}

Threshold Validation:

// Before removing owner
if (newOwners.length < threshold) {
  throw new Error("Threshold would exceed owner count");
}

Protected Operations:

• Adding/removing owners
• Updating threshold
• Approving transactions
• Executing transactions

4. Rate Limiting

Rate limiting prevents DoS attacks and abuse.

Implementation:

import { RateLimiter } from "@/utils/security";

const limiter = new RateLimiter(10, 60000); // 10 requests per minute
if (!limiter.checkLimit(userAddress)) {
  throw new Error("Rate limit exceeded");
}

Limits:

• Default: 10 requests per minute per address
• Configurable per use case
• Automatic cleanup of old entries

5. Replay Protection

Prevents replay attacks on messages and transactions.

Message Replay Protection:

• Timestamp-based validation
• 1-second replay window
• Message ID tracking
• Automatic cleanup

Transaction Replay Protection:

• Nonce management
• Transaction deduplication
• Transaction expiration (1 hour)
• Hash-based duplicate detection

6. Nonce Management

Automatic nonce management prevents transaction conflicts.

Implementation:

import { NonceManager } from "@/utils/security";

const nonceManager = new NonceManager(provider);
const nonce = await nonceManager.getNextNonce(address);

Features:

• Automatic nonce tracking
• On-chain nonce synchronization
• Nonce refresh after execution
• Per-address nonce management

Security Best Practices

For Developers

1. Always Validate Input

// ✅ Good
const validation = validateAddress(address);
if (!validation.valid) {
  throw new Error(validation.error);
}

// ❌ Bad
const address = userInput; // No validation

2. Use Secure Storage

// ✅ Good
const storage = new SecureStorage();
await storage.setItem("data", JSON.stringify(sensitiveData));

// ❌ Bad
localStorage.setItem("data", JSON.stringify(sensitiveData));

3. Check Authorization

// ✅ Good
if (!isOwner(callerAddress)) {
  throw new Error("Unauthorized");
}

// ❌ Bad
// No authorization check

4. Handle Errors Securely

// ✅ Good
try {
  await operation();
} catch (error: any) {
  monitoring.error("Operation failed", error);
  // Don't expose sensitive error details
  throw new Error("Operation failed");
}

// ❌ Bad
catch (error) {
  console.error(error); // May expose sensitive info
}

5. Use Rate Limiting

// ✅ Good
if (!rateLimiter.checkLimit(userAddress)) {
  throw new Error("Rate limit exceeded");
}

// ❌ Bad
// No rate limiting

For Users

1. Verify Addresses

• Always verify addresses before transactions
• Use checksummed addresses
• Double-check recipient addresses

2. Review Transactions

• Review all transaction details
• Verify gas estimates
• Check transaction data

3. Protect Private Keys

• Never share private keys
• Use hardware wallets when possible
• Enable multi-sig for large wallets

4. Monitor Activity

• Regularly check transaction history
• Monitor for unauthorized approvals
• Review wallet configurations

Security Architecture

Encryption Flow

User Data
    │
    ▼
Input Validation
    │
    ▼
Encryption (AES-GCM)
    │
    ▼
Encrypted Storage
    │
    ▼
Decryption (on read)
    │
    ▼
Validated Output

Validation Flow

User Input
    │
    ▼
Format Validation
    │
    ▼
Type Validation
    │
    ▼
Range Validation
    │
    ▼
Business Logic Validation
    │
    ▼
Sanitization
    │
    ▼
Processed Input

Authorization Flow

Operation Request
    │
    ▼
Extract Caller Address
    │
    ▼
Verify Owner Status
    │
    ▼
Check Threshold
    │
    ▼
Verify Permissions
    │
    ▼
Execute Operation

Security Testing

Running Security Tests

# Run all security tests
pnpm test:security

# Run specific security test
pnpm test __tests__/security.test.ts

Security Test Coverage

• ✅ Address validation
• ✅ Transaction validation
• ✅ Encryption/decryption
• ✅ Rate limiting
• ✅ Nonce management
• ✅ Replay protection
• ✅ Access control

Security Audit

A comprehensive security audit has been conducted. See:

• SECURITY_AUDIT.md - Full security audit
• SECURITY_FIXES.md - Security fixes implemented
• SECURITY_SUMMARY.md - Executive summary

Audit Results

Status: ✅ All critical vulnerabilities addressed

Security Posture: 🟢 Low Risk (down from 🔴 High Risk)

Key Improvements:

• Encrypted storage implemented
• Comprehensive validation added
• Access control implemented
• Replay protection active
• Rate limiting enforced

Incident Response

Security Incident Procedure

1. Identify - Detect and confirm security incident
2. Contain - Isolate affected systems
3. Assess - Evaluate impact and scope
4. Remediate - Fix vulnerabilities
5. Document - Record incident and response
6. Notify - Inform affected users if necessary

Reporting Security Issues

If you discover a security vulnerability:

1. DO NOT open a public issue
2. Email security team directly
3. Provide detailed information
4. Allow time for fix before disclosure

Security Checklist

Development Checklist

• All inputs validated
• Sensitive data encrypted
• Authorization checks in place
• Rate limiting implemented
• Error handling secure
• No sensitive data in logs
• Dependencies up to date
• Security tests passing

Deployment Checklist

• Security audit completed
• All tests passing
• Error tracking configured
• Monitoring active
• HTTPS enforced
• Security headers set
• Backup procedures ready
• Incident response plan ready

Security Resources

• OWASP Top 10
• Ethereum Security Best Practices
• Web3 Security
• Smart Contract Security

Security Updates

Security is an ongoing process. Regular updates include:

• Dependency updates
• Security patches
• New security features
• Improved validation
• Enhanced monitoring

Stay updated by:

• Monitoring security advisories
• Reviewing changelogs
• Running security audits
• Keeping dependencies current