Best Practices to Develop Secure Mobile Apps

There is high demand for mobile apps because many companies and businesses use them to enhance interaction between users and their products. Most users have mobile applications for different purposes, i.e., chatting, video calling, shopping, physical activities, dating, learning, etc. The apps operate on different operating systems, i.e., Android and iOS, whereby some are free while others are paid. 

Due to this, hackers are always looking to find vulnerabilities in the applications to steal sensitive information, spread malware, and ruin the company’s reputation. Software teams and developers should follow best practices during the development process to have secure mobile apps. Companies should pay attention to mobile app security.

According to Synopsys Cybersecurity Research Center (CyRC), many vulnerabilities exist on the most downloaded apps, and hackers take advantage of that to extend their attacks. This guide will discuss some of the commonly used practices by developers to secure mobile apps.

Best Practices to Develop Secure Mobile Apps

It is the role of every company and developer to ensure they have the best practices as a company. Most are easy; you can incorporate them into the team workflow. In other instances, it can force the company to hire additional skilled individuals like cybersecurity professionals to conduct penetration testing. Some of the practices include:

• Use of encryption.
•  Performing penetration testing.
•  Use of authentication and authorization.
•  Using best coding practices to write secure code.
•  Use of Secure Data Storage.
• Ensuring all the services and dependencies are up to date.
• Use of the right permissions during the development process.
• Using secure communication between your app and other applications.
• Applying temper detection technologies.
• Use of Cryptography.

1. Use of Encryption

Some developers leave bugs and vulnerabilities that hackers exploit during the development process. The hackers take control of your app, change the code and insert malware or a virus to steal data and supply it to other third-party vendors where users can download it, and chances are being hacked. Encryption and hashing change your code into cipher text that is unreadable by hackers. 

It gives hackers a hard time when they try to understand the code. We have several techniques and tools to achieve the best result. It would be best to encrypt your database using different file methodologies to keep your mobile app’s data safe. 

2. Performing Penetration Testing

Before launching any application, all software teams must take their application through testing. It eliminates all the loopholes and susceptibilities that may occur in the application. It leaves hackers with little chance of hacking your application. Most software teams skip the penetration processes for a faster launch, which is dangerous.

Companies must hire several security experts and penetration testers to help them find bugs. It may be hard if it is a startup, and you can still go with those who work freelancing. One of the common tools companies use for testing is SAST (Static Application Security Testing) which tests all the app code and checks for any loopholes.

3. Use of Authentication and Authorization

Authentication involves using usernames, passwords, access keys, and SSO flows to prove identities, while authorization checks the right permissions during the authentication to access specific application resources. Some of the best ways to improve authentication and authorization include:

• Use of SSL certificates that are valid and active.
• Implementation of biometric identification, i.e., retina and fingerprints.
• Ensure your applications only accept alphanumeric passwords and encourage users to change their passwords after a certain period.
• Use several authentication methods, like using a one-time password (OTP) when users try to log into their accounts. 

4. Using Best Coding Practices to Write Secure Code

Developers should learn to build mobile applications free from bugs and vulnerabilities. Writing clean and minifying it reduces the chances of reverse engineering it for other purposes.

After the coding process, test all vulnerabilities and bugs in the code. The team must also ensure the code is easily patchable to avoid hackers. Testing can be a challenging process, but at the end of the day, it saves the app developers. 

Conduct code audits regularly to ensure there are no loopholes. Test the application using different system emulators from other operating systems to see how the mobile app behaves in different environments.

5. Implementation of Code Signing Certificate

A Code Signing certificate is essential for software code integrity and security. Once you install a code signing certificate, it increases the chances of software downloads and establishes the publisher’s authenticity. Software publishers can ensure end users that they are downloading legitimate software/app/drivers. The code is digitally signed and has not been altered since it is signed. 

6. Use of Secure Data Storage

Most software developers use the device memory when storing the application data. It can expose your sensitive data and end up losing it to hackers. Most users are very keen when granting your mobile application permission to access the data. Store the data well to earn the user’s trust.

Some of the ways to implement secure data storage include:

• When dealing with sensitive private data, store it under internal storage and limit the number of applications that can access it. Add a possibility where the user can delete the data during uninstallation automatically.
• Sometimes, the mobile application may use corrupted files under the external storage, creating a logic that handles all the corrupt files and data.
• If there are files you feel are not sensitive, and other mobile apps rely on them, you can store the data on external storage and manage access to the media and other files.
• Practice storing all the non-sensitive data in the application cache. When dealing with cached data, use getCacheDir() for caches that are 1MB and below and getExternalCacheDir() for more than 1 MB.

7. Ensuring All the Services and Dependencies Are up to Date

• Applications use external APIs and libraries to automate some of the tasks. The apps keep all the application information; you must be keen when using them. To ensure your application is safe, follow the steps below:
• Update the dependencies. Before publishing your applications, ensure that all the SDKs, dependencies, and libraries are current. When using first-hand frameworks under the Android Studio, use tools like SDK manager.
• For external or third-party libraries and dependencies, ensure you visit their official websites and look if they have any new updates and install them on your site.

8. Use of the Right Permissions During the Development Process

Use privileges and permissions during the design process to reduce data exposure to hackers. It is good to use a small number of app permissions and even stop them when they are not in use. It helps in providing only the required data to limited users. Other practices to ensure the right permissions include:

• Sharing the application data with other mobile apps securely by using content:// URIs for FileProvider instances, understanding how to use read-only and write-only permissions where necessary, and FLAG_GRANT_READ_URI_PERMISSION and FLAG_GRANT_WRITE_URI_PERMISSION flags for providing one-time access to application data by the users.
• Using intents to delay all the requests to another app with the same permissions.

9. Use of the Right Permissions During the Development Process

Most mobile applications operate on client and server architecture, which rely on each other. You have to protect all the APIs and backends connected to your code. When data is moved from your app to other applications, you must protect the data from hackers who may have other plans.

To have secure communication, implement some of the methods below:

• Use the HTML message channel if your mobile application runs Android 6.0 and uses JavaScript interfaces.
• If your application runs on android 4.1.1 and below, use the Content Provider object to prevent your mobile application from sending data to another application whose ownership you do not know.
• When using WebView in your application, restrict the type of content loaded by the object using allow list.
• Use a trusted TLS certificate if your application communicates with the web server.
• Create your trust manager that does not accept all TLS when communicating with web servers.

10. Using Temper Detection Technologies

A security methodology prevents your mobile application code from working if it is tampered with. When a hacker attempts to access your code and inject a virus or Trojan, you will be notified and should take action. It prevents your mobile application from being attacked by viruses and other vulnerabilities.

11. Use of Cryptography

When deploying cryptography techniques, avoid using the old ones and start deploying the new ones. Older ones like MD5 and SHA1 are outdated, and you need to work with the modern ones like AES with 512-bit encryption and 256-bit encryption and opt for SHA-256 during hashing.

Conclusion

Smartphone users keep increasing, and your role as a developer is to ensure security is your priority. It prevents you from having incidents where hackers access your application and start asking for ransom and other requirements. It can lead to users uninstalling your application and affecting your revenue. 

We also need to educate our users on where to download their mobile apps and how to stay safe from hackers. For some companies, it isn’t easy to implement all this. All you can do is hire a security expert to test your application before publishing it for usage.