Securing Mobile Applications: Best Practices for iOS and Android Developers - Part 5

Muhammad Mohsin RazaPosted on March 17, 2025

4-5 Min Read Time

With this, we’ve reached the final blog of our series.

Throughout this journey, we’ve covered essential aspects of mobile application security, starting with Architecture, Design, and Threat Modeling Requirements, where we discussed strategies to safeguard applications against potential threats. We then explored Data Storage and Privacy Measures, outlining best practices to protect user information from unauthorized access and breaches. Next, we dived into Authentication and Session Management Requirements, highlighting secure methods for user verification. 

In our previous blog, we learned about the Mobile Security and Platform Interaction Requirements, focusing on secure integrations and platform-specific security considerations.

Now, in this final part, we’ll shift our focus to Code Quality and Build Setting Requirements—exploring best practices for writing maintainable code, optimizing performance, and streamlining the development process.

Code Quality And Build Setting Requirements

The set of security measures in this category has a purpose to make sure that basic security coding practices are followed in developing the app. 

When the app was built, it was in release mode and had settings that were right for a release build (e.g., non-debuggable).

The app shared among the testers or to the public should be in release mode. This is to make sure that the app is non-debuggable so that the possibility of attaching debuggers or reverse engineering can be minimized. 

Scenario: 

The app is under development and the team started sending debug builds to external developers or the public for testing. 

Attack: 

Apps with no proper release settings are at risk of attacks which can use debugging tools (such as Android’s adb or Xcode’s debugger) to gain access to sensitive information or even change the app’s behavior. Attackers can also reverse engineer the app’s code to learn more about vulnerabilities or sensitive logic in the app's code.  

Mitigation:

The app should be shared with release settings and the app should be configured for a production environment. This will make sure that the app is non-debuggable, which minimizes the risk of attaching debuggers or reverse engineering tools to the app.

Debugging and developer assistance codes (e.g., test codes, backdoors, hidden settings) have been removed. The app lacks comprehensive error logging or debugging messages.

This approach strengthens security by minimizing the amount of information available that could be used to identify vulnerabilities or facilitate an attack.

All third-party components the mobile app uses, such as libraries and frameworks, are identified and checked for known vulnerabilities.

Scenario: 

The mobile app uses multiple third-party libraries for its functionality and these libraries are outdated and with a number of vulnerabilities.  

Attack: 

Attackers can exploit these vulnerable libraries and can take control of data. For example, outdated versions of libraries like OpenSSL or Jackson have been targeted in past security breaches. 

Mitigation:

Third-party libraries and frameworks used in apps should be scanned regularly for known vulnerabilities using automated tools like OWASP. If any vulnerabilities are found, they should be patched and the app should be updated as soon as possible.

The app captures and handles possible exceptions.

The app should capture and handle possible exceptions to ensure smooth operation and prevent crashes or unexpected behavior. 

Scenario: 

The mobile app may encounter unexpected events or errors during its execution. It may address network issues, server-side errors, or incorrect inputs. Inappropriate handling of these mistakes might cause crashes, bad user experience, or access to private data.

Attack: 

If you do not handle errors promptly, the app could crash, which would be bad for users and could cause data loss. Exceptions that aren't caught may show thorough error messages that include private information like where the error happened. This can also include the user's credentials or information about the internal system. 

Mitigation:

The app should catch exceptions and handle them without crashing. It can show user-friendly messages like "Something went wrong, please try again" instead of raw system errors.

In The End

Securing mobile applications is no small feat, but it’s a critical responsibility for developers. By integrating security from the start, minimizing attack surfaces, and adhering to best practices, you can build apps that protect user data and maintain trust. Remember, security isn’t a one-time task—it’s an ongoing process. 

Stay informed, keep your tools updated, and always prioritize the user’s privacy and safety. After all, a secure app isn’t just good for your users—it’s good for your reputation too.