ensuring-mobile-security

Security Standards

When to use this skill

• When handling user credentials or sensitive personal data (PII).
• When configuring API calls and networking.
• When implementing authentication logic.
• When preparing the app for a production release.

Data Storage

• Credentials: NEVER store passwords, tokens, or API keys in AsyncStorage, SharedPreferences, UserDefaults (iOS), or localstorage (Web).
  • Use: Secure storage wrappers like expo-secure-store or flutter_secure_storage which leverage the OS Keychain/​Keystore.
• Local Data: Encrypt sensitive databases (e.g., Realm/​SQLite encryption) if they contain user data.
• Cleanup: Wipe all sensitive local data and tokens immediately upon logout.

Network Security

• Transport: Enforce HTTPS for all connections. Block cleartext traffic in Info.plist (iOS) and AndroidManifest.xml (Android).
• Certificate Pinning: Implement certificate pinning for critical APIs to prevent MitM attacks.
• Validation: Strict SSL certificate validation.
• Logging: NEVER log sensitive headers (Auth tokens) or request bodies containing PII in production or crash reports.

Authentication

• Protocol: Use industry standards like OAuth 2.0 / OIDC. Avoid custom auth schemes.
• Biometrics: Use FaceID/​TouchID for quick re-auth where appropriate, but always fallback to PIN/​Password.
• Sessions:
  • Implement short-lived access tokens and long-lived refresh tokens.
  • Enforce local session timeouts for banking/​fintech apps.
• Privacy: Obscure the app preview in the recent apps switcher (Task Manager) to prevent screenshotting sensitive screens.

Code Security

• Production Builds:
  • Enable code obfuscation (ProGuard/​R8 for Android).
  • Strip debug symbols.
  • Remove all console.log / print statements using build tools (e.g., babel-plugin-transform-remove-console).
• Validation: Sanitize and validate ALL user inputs on both client and server to prevent injection attacks.
• Rate Limiting: Handle 429 Too Many Requests gracefully.