Secrets Detection

Secrets Detection

Find and prevent leaked API keys, passwords, and credentials in your codebase.

When to Use

• Reviewing code for hardcoded secrets
• Setting up CI/CD security checks
• Auditing git history for leaks
• Configuring pre-commit hooks
• Responding to secret exposure incidents

Common Secret Patterns

Detection Tools

1. Gitleaks (Recommended)

# Install
brew install gitleaks

# Scan current directory
gitleaks detect -v

# Scan git history
gitleaks detect --source . -v

# CI/CD integration
gitleaks detect --source . --exit-code 1

# .gitleaks.toml - Custom rules
[allowlist]
  paths = [
    '''vendor/''',
    '''node_modules/''',
    '''\.test\.'''
  ]

[[rules]]
  description = "Custom API Key"
  id = "custom-api-key"
  regex = '''myapp_[a-zA-Z0-9]{32}'''
  tags = ["key", "custom"]

2. git-secrets (AWS)

# Install
brew install git-secrets

# Add AWS patterns
git secrets --register-aws

# Scan repository
git secrets --scan

# Install hooks
git secrets --install

3. TruffleHog

# Scan repository
trufflehog git file://. --only-verified

# Scan GitHub org
trufflehog github --org=myorg --only-verified

# CI/CD
trufflehog git file://. --fail --only-verified

Pre-Commit Hooks

Husky + lint-staged

npm install -D husky lint-staged
npx husky init

// package.json
{
  "lint-staged": {
    "*.{js,ts,jsx,tsx}": [
      "gitleaks detect --no-git -v"
    ]
  }
}

# .husky/pre-commit
#!/bin/sh
npx lint-staged
gitleaks protect --staged -v

Pre-commit Framework

# .pre-commit-config.yaml
repos:
  - repo: https://github.com/gitleaks/gitleaks
    rev: v8.18.0
    hooks:
      - id: gitleaks

  - repo: https://github.com/awslabs/git-secrets
    rev: master
    hooks:
      - id: git-secrets

  - repo: https://github.com/Yelp/detect-secrets
    rev: v1.4.0
    hooks:
      - id: detect-secrets
        args: ['--baseline', '.secrets.baseline']

# Install
pip install pre-commit
pre-commit install

CI/CD Integration

GitHub Actions

name: Secret Scanning

on: [push, pull_request]

jobs:
  gitleaks:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Gitleaks
        uses: gitleaks/gitleaks-action@v2
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

  trufflehog:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: TruffleHog
        uses: trufflesecurity/trufflehog@main
        with:
          extra_args: --only-verified

GitLab CI

secret_detection:
  stage: test
  image: zricethezav/gitleaks:latest
  script:
    - gitleaks detect --source . --exit-code 1 -v
  allow_failure: false

Safe Secrets Management

Environment Variables

// Load from environment
const config = {
  apiKey: process.env.API_KEY,
  dbPassword: process.env.DB_PASSWORD,
  jwtSecret: process.env.JWT_SECRET
};

// Validate required secrets
const requiredSecrets = ['API_KEY', 'DB_PASSWORD', 'JWT_SECRET'];
for (const secret of requiredSecrets) {
  if (!process.env[secret]) {
    throw new Error(`Missing required secret: ${secret}`);
  }
}

.env Files (Development Only)

# .env.example (commit this)
API_KEY=your_api_key_here
DB_PASSWORD=your_db_password_here

# .env (NEVER commit)
API_KEY=sk_live_actual_key_12345
DB_PASSWORD=actual_password

# .gitignore
.env
.env.local
.env.*.local
*.pem
*.key

Secrets Manager Integration

// AWS Secrets Manager
const { SecretsManager } = require('@aws-sdk/client-secrets-manager');

async function getSecret(secretName) {
  const client = new SecretsManager({ region: 'us-east-1' });
  const response = await client.getSecretValue({ SecretId: secretName });
  return JSON.parse(response.SecretString);
}

// HashiCorp Vault
const vault = require('node-vault')({
  endpoint: process.env.VAULT_ADDR,
  token: process.env.VAULT_TOKEN
});

async function getVaultSecret(path) {
  const { data } = await vault.read(path);
  return data.data;
}

Incident Response: Secret Leaked

# 1. Immediately revoke the secret
# - AWS: IAM console -> Delete access key
# - GitHub: Settings -> Developer settings -> Delete token
# - Stripe: Dashboard -> API keys -> Roll key

# 2. Remove from git history
git filter-branch --force --index-filter \
  "git rm --cached --ignore-unmatch path/to/secret/file" \
  --prune-empty --tag-name-filter cat -- --all

# Or use BFG Repo-Cleaner (faster)
bfg --delete-files secret-file.txt
bfg --replace-text secrets.txt

# 3. Force push (coordinate with team!)
git push origin --force --all
git push origin --force --tags

# 4. Audit for unauthorized access
# Check service logs for the compromised credential

# 5. Generate new secret and update references

Code Review Checklist

• No hardcoded API keys or passwords
• No private keys in repository
• No credentials in configuration files
• Environment variables used for secrets
• .env files in .gitignore
• Pre-commit hooks configured
• CI/CD secret scanning enabled
• Secrets manager used in production
• Example config files don't contain real secrets

Best Practices

1. Never Commit Secrets: Use pre-commit hooks
2. Use Secrets Managers: Vault, AWS Secrets Manager
3. Rotate Regularly: Automate secret rotation
4. Audit Access: Log who accesses secrets
5. Least Privilege: Minimal permissions for each secret
6. Scan Git History: Secrets may be in old commits
7. Act Fast on Leaks: Revoke immediately, then clean up