Ensuring Security in Mobile App Development

Today let’s talk about something that doesn't always get much attention but is absolutely critical and important, that is the mobile app security. If you think “My app is fine, who would ever want to hack it? then think again because Security threats aren’t just for big apps, even small apps can be a target of hackers.

Do not worry, securing your mobile app actually doesn’t have to be overwhelming. By understanding common risks following industry standard and taking a few key precautions, you can protect your user's data and keep your app safe from attackers.

So, what are the biggest security challenges, and how do we stay ahead of them? Let's take a closer look.

Common Security Risks in Mobile Apps

1. OWASP Mobile Top 10 Risks (2024 Updated from OWASP)

• M1: Improper Credential Usage
• M2: Inadequate Supply Chain Security
• M3: Insecure Authentication/Authorization
• M4: Insufficient Input/Output Validation
• M5: Insecure Communication
• M6: Inadequate Privacy Controls
• M7: Insufficient Binary Protections
• M8: Security Misconfiguration
• M9: Insecure Data Storage
• M10: Insufficient Cryptography

These are the most common security problems found in mobile apps according to OWASP standards.

Let's covers some of the key risks that i think it's common that developers might overlook in development:

Improper Credential Usage (M1)

If you hardcode credential or api keys in mobile app , it can be extracted through reverse engineering, giving the attackers access to the account or the services. If it's commited into the repository, someone with access could leak them by mistake

Insecure Authentication/Authorization (M3)

Don't just rely on local authentication because redentials can be stolen, authentication can be bypassed, and there’s no centralized control or proper session management. Server authentication is the way to go since it keeps credentials secure, allows centralized user management, supports multi-factor authentication (MFA).

Insecure Communication (M5)

When mobile app sends personal data to a server without using a secure HTTPS (SSL/TLS) connection. This means the data is transmitted in plain text, making it easy for hackers to intercept and steal the information while it’s traveling over the internet. As a result, any sensitive or private data could be exposed, putting user privacy at risk.

A hacker can sit between the app and the real server using a fake certificate (Man-in-the-Middle (MITM) Attacks) , intercepting or even altering data.

Insufficient Binary Protections (M7)

If your app isn’t properly obfuscated, attackers can easily reverse engineer it, exposing sensitive logic and making it easier to bypass security checks, unlock paid features, or inject malicious code. Without obfuscation, tools can decompile your app in minutes, revealing key functions and vulnerabilities. This opens the door for modified versions to be redistributed damaging your reputation. In the worst case, the project's functionality could be replicated and released as a competing product.

Security Misconfiguration (M8)

Avoid requesting unnecessary permissions in your app. It opens the door for hackers to collect user contacts, location, or passwords, leading to identity theft or fraud. In a worse case, it can also get access to payment details, which can result in financial loss. This has to be extra careful especially when choosing 3rd party package where sometimes some of the pacakage has unknown usage of permission required.

Remove test features and debug tools before releasing your app to prevent extra features from being exploited.

Insecure Data Storage (M9)

Storing sensitive data without encryption poses a major risk. Encrypting the data before storing adds an extra layer of security, making it harder for hackers to retrieve the actual value even if they gain access.

How Hackers Exploit Vulnerabilities

Hackers can use reverse engineering tools to break into apps. Some common tools hackers use include:

• Magisk – Grants root access to Android devices.
• Taurine - Jailbreak ios devices .
• Frida – Allows hackers to inject code and extract data. (ios & anroid)
• APKTool – Helps break down and analyze APK files. A Beginner's Guide to Reverse Engineering Android Applications
• IDA PRO – Disassemble and analyzing iOS binaries.

How to Protect Your Mobile App

These are some of the measure that can be taken to eliminate the risks of the above risk mentioned:

1. Avoid hardcode credentials

Remove hardcode credentials and api keys. Use environment variables instead of hardcoding keys / secrets.

2. Certificate pinning

Implement certifcate pinning if possible because it ensures that a mobile app only trusts a specific certificate or public key from the real server. When the app connects to the server, it checks if the certificate matches the pinned one. If it doesn’t, the connection is blocked stopping hackers from intercepting and stealing sensitive data. Here's a package for certificate Pinning such as http_certificate_pinning or react-native-ssl-pinning

2. Encrypt Sensitive Data

Never store passwords or tokens in plain text. Use an encrypted storage such as Flutter Secure Storage to encrypt your data or react-native-keychain which they encrypt the values before storing in the device.

3. Use a RASP Package (Runtime Application Self-Protection)

It helps detect and block security threats in real time. A RASP package can warn your app when an attack is happening. Some RASP packages like freeRasp provide features like detection and prevention of root/jailbreak devices, hooking framework, and untrusted installation methods.

4. Automate Security Testing

Frequently scan code for vulnerabilities and integrate security checks into your CI/CD pipeline such as integrating with MOBSF Scans in CICD pipeline as discussed in this article

Conclusion

Last advice is to frequently update your mobile SDK (flutter / RN / Native iOS & android) in you project. You might think how does this related to security, well it's a measure to ensure if the team of flutter or react native or native iOS & android have release an update that is fixing or enhancing the security, then it might be crucial to upgrade to include that enhancement and fix.

Securing your mobile app isn't a one time job, it's something you need to keep working on continuously because tech is changing fast. Some steps or practice might seems small but it actually can impact alot if being ignored. By following best coding practices and stay updated with the OWASP MAS checklist, we can reduce the risk of being hacked and ensure user data security.

Written by Low Wan Ting