How to secure your Flutter Application?

• General

In this article, we will see about the most effective practices to minimize the risk for any security exploit in Flutter Apps. Also, we will put as many roadblocks to secure your flutter application created by the flutter app development company.

How to secure your Flutter Application?

One of the first things an attacker will look for when targeting an app is to see if they can intercept any of the data passing between it and your server’s backend.

Protecting the communication Layer

1) Employing strong encryption:

This can be done using protocols such as SSL and TLS. These protocols are easy to add to your code and very difficult to compromise. Let’s assume you’re dealing with sensitive data. In that case, you can build a VPNtype solution directly in your app.

2) Restricting network traffic.

You can restrict network traffic on your Flutter App. One way to restrict traffic or connection is to whitelist your domain. In such way you can restrict unwanted traffic to your Flutter Application.

3) Certificate Pinning

You can implement SSL pinning to solve the Man In The Middle attack. In simple terms, get the server certificate file from the backend developer and fix the certificate on every API call. So the HTTP client will take this certificate as a trustable one. Now if MITM happens and the app gets some bad certificate, the API calls will be broken due to a Handshake error.

4) Make Authentication Bulletproof

Apart from the app’s data stream, the second most common attack vector to eliminate is the weakness of the authentication method. Therefore, two-factor authentication on the server is required and worth implementing. In addition, you need to be careful about processing methods such as key exchange. Also, make sure are using the encryption to keep those transactions secure.

Protecting the Application:

1) Protecting the communication Layer

Compiled binaries and app code can be developed in reverse. Some things you can expose include strings, method and class names, API keys, and so on. These data are either original text or plain text.

-from the dart side you can use the –obfuscate parameter whenever you are building your Flutter app.

flutter build appbundle --obfuscate --split-debug-info=/<directory>

and from the native side, you need to handle that by :

android

In your /android/app/build.gradle file, add the following:

android {
  ...
  buildTypes {
    release {
      signingConfig signingConfigs.release
      minifyEnabled true
      useProguard true
      proguardFiles 
getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
  }
}

Create a ProGuard configuration file in /android/app/proguard-rules.pro:

# Flutter
-keep class io.flutter.app.** { *; }
-keep class io.flutter.plugin.**  { *; }
-keep class io.flutter.util.**  { *; }
-keep class io.flutter.view.**  { *; }
-keep class io.flutter.**  { *; }
-keep class io.flutter.plugins.**  { *; }

2) Jailbroken and rooted devices

Rooted Android devices and Jailbroken iOS device have more privileges compared to regular systems. It can introduce malware to the user’s device and bypass the normal behavior of the device. There is package in Flutter that is flutter_jailbreak_detection. You can use this package to detect if your app is running on a jailbroken or rooted device. Use Root Beer on Android and DTT Jailbreak Detection on iOS. Moreover, it is very easy to use:

import 'package:flutter_jailbreak_detection/flutter_jailbreak_detection.dart';

bool jailbroken = await FlutterJailbreakDetection.jailbroken;
bool developerMode = await FlutterJailbreakDetection.developerMode; // android only.

3) Secure user data

Do not use sharing settings or SQLite to store sensitive user data. This is because it is easy to open on any device. So, you will be required to encrypt the stored data. For that, you can use flutter_secure_storage. This package uses Keystore for Android and Keychains for iOS.

4) Use local authentication

Suppose the user phone has been stolen and your application is installed on it and it has some payment information. To prevent any access to your app you should use Biometrics authentication by using this package.

Conclusion:

Thanks for being with us on a Flutter Journey!

So, in this article, we have seen the How to secure your Flutter Application. Always use safe and best practices to secure any application in Flutter. Also, feel free to comment and provide any other suggestions regarding Flutter.

Written by Abhishek Dhanani

Abhishek Dhanani, a skilled software developer with 3+ years of experience, masters Dart, JavaScript, TypeScript, and frameworks like Flutter and NodeJS. Proficient in MySQL, Firebase, and cloud platforms AWS and GCP, he delivers innovative digital solutions.