How Developers Can Build More Secure Mobile Apps

Mobile apps collect large amounts of data to function effectively and deliver personalized experiences. Navigation apps depend on location permissions, banking apps need financial details, and social media apps use personal information.

However, with weak mobile app security, cybercriminals can access this data and use it for fraud, identity theft, phishing scams, and other malicious activities.

App developers who don’t take data protection seriously can find themselves in legal trouble, face regulatory penalties, suffer reputational damage, and lose user trust.

To secure user data the right way, you need to incorporate it into every step of your company. From development practices to infrastructure decisions to ongoing maintenance, prioritizing security will save you headaches in the long run.

This article guides you through the full development life cycle and shows you exactly how to strengthen your security and protect users of your product. Use these eight actionable steps to build safer apps that can adapt to future security challenges.

Additional reading: “Users Are Limiting App Permissions to Enhance Data Security & Privacy.”

1. Build Security into the Development Process from Day One

App companies deal with massive amounts of data that can both strengthen analytics and improve user experience. Despite this upside, it also means taking on a lot of responsibility. Companies that start thinking about security toward the end of the development process expose themselves to major risks, including data breaches, regulatory penalties, and lawsuits.

To avoid this, you need to build security into your development process from day one. A Secure Development Lifecycle (SDL) weaves security measures into each stage of development rather than treating it as a final checkpoint.

According Ilya Budko, the CEO at Weelorum, shifting the security process left is key to ensuring apps are secure. “What actually works, in my experience, is a shift from “security as a checklist” to “security as a process”: automated dependency scanning in CI/CD, periodic re-audits of critical modules, shift-left (security review at the planning stage of a feature, not at release), and a team culture where a junior engineer is comfortable saying ‘this looks suspicious.’”

Start the planning stage before writing a single line of code by figuring out what types of data you’ll be handling. With this information, map out how it will move through the app, then locate potential points of vulnerability where attackers may try to ambush the system.

Make sure your developers have a strong foundation in secure coding practices. They should be familiar with frameworks like the OWASP Mobile Top 10, a guide for identifying and preventing the most common mobile security risks, at the bare minimum.

Use continuous testing to ensure the app's safety. Integrating static and dynamic application security testing (SAST/DAST) into your CI/CD pipeline also allows you to identify weaknesses and vulnerabilities before launch, so they don’t become problems when customers have access to the app.

2. Lock Down Data Storage and Transmission

Once initial security measures are in place, you must ensure the safe collection and storage of customer data. Personal data should be encrypted at all times.

In fact, most IT teams prioritize encrypting data in transit and at rest (43%) and running regular security audits (44%) to secure their data.

Storing data locally on a user’s device might seem convenient, but it can lead to big problems. If a customer’s phone is lost or stolen, it can make their data easy for cybercriminals to access.

“After years of working on mobile products, I can say with confidence that the single most repeated mistake is insecure data storage,” says Budko. “Teams write tokens, refresh tokens, sometimes PII and API keys, straight in SharedPreferences on Android or UserDefaults on iOS. On a non-jailbroken device, it's “sort of” protected.”

He continues, “But in real life, devices get lost, sent to repair shops, passed to support technicians, or have shady free apps installed by a kid in the household — and suddenly that token is gone.”

Despite this, sometimes storing data locally is unavoidable. If this is the case, developers should use the platform’s secure storage, such as Keychain on iOS or Keystone on Android, to protect data.

Data transmission is another security emphasis. When data moves from one system to another, cybercriminals can use techniques, such as man-in-the-middle attacks, to capture sensitive information. Developers must enforce Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols for all network communication. They should also implement certificate pinning to prevent successful attacks.

Remember, the less data is collected and stored in the first place, the less risk there is. Data minimization, or collecting and storing only what’s absolutely necessary, means less exposure for both you and your customers. You can’t leak what you don’t store.

3. Strengthen Authentication and Access Controls

Apps with weak authentication systems make it easier for hackers to get data. One of the best ways to strengthen user accounts and internal systems alike is by requiring multi-factor authentication.

Instead of logging in with only a password, users must use a second factor to verify themselves, such as an authenticator code, biometrics, or a one-time passcode (OTP). Avoiding passwords entirely is possible with protocols like OAuth 2.0, which use tokens to verify user identity.

You can also set session timeouts that limit how long a user can stay logged in without activity. Once the session ends, users will have to log back in using their authentication methods. Requiring re-authentication for sensitive actions can add another layer of security on top of that.

The best way to keep data safe is to restrict access to it. The principle of least privilege is the idea that any user, service, or API key should only have the minimum level of access needed to function.  Companies that apply this across their entire stack have fewer people accessing sensitive data and, therefore, less concern.

4. Secure Your APIs

APIs are interfaces that allow software components to communicate with each other. This makes them a favorite target for hackers. Since you don’t have control over what kinds of requests come in from the client side, you need to focus on validating and sanitizing all input on the server side. You do, however, have control over the number of requests coming in.

A favorite tactic among hackers is to overwhelm the system with requests to force access. Rate limiting and throttling restrict the number of requests a user or device can make within a given period of time. This prevents bad actors from gaining access to your system through brute force.

It’s also important to use API gateways to centralize authentication, logging, and monitoring. This enhances security by creating an environment where administrators can manage API traffic.

Poorly planned messaging can also lead to breaches. If your error messages provide too many details about the issue, you may be giving cybercriminals a roadmap for your architecture. You should also be careful not to expose internal endpoints, as hackers actively look to exploit these.

5. Test Relentlessly and from Multiple Angles

The best way to know if your security system works is to test it. Regular penetration testing is the best way to find holes in your defenses. Take a multipronged approach to testing. Use automated tools to scan and detect known issues that you may have missed. Then use humans impersonating hackers to secure yourself against new, creative techniques that could be in the works.

Conduct code reviews focused specifically on security, rather than lumping them in with functionality reviews. Try out your security system across different devices and OS versions, not just emulators, to identify real issues. You should also schedule third-party security audits annually and after any launches or architectural changes.

6. Manage Third-Party Dependencies and SDKs Carefully

Developers can take advantage of third-party libraries and Software Development Kits (SDKs) before integration to speed up production timelines and improve the apps. However, these can become colossal risks if not properly vetted. Whenever an external service pairs with an app, it adds another target for hackers.

Before adding another dependency, make sure you understand exactly what data it collects, where it’s stored, and the permissions required. Then, make sure to keep it updated at all times and monitor for known vulnerabilities with tools like Dependabot or Snyk.

Don’t keep any unused libraries associated with your app. It’s best practice to have a vendor security review process that evaluates any new integration that deals with user data.

7. Plan for Incidents Before They Happen

You can take every precaution possible to keep data safe, but breaches can still happen. Creating a plan of action can help you act quickly when things go wrong to protect your customers and company.

First, you need an incident response plan that covers detection, containment, communication, and recovery of an attack. Regularly drill this plan and play out different scenarios. These simulations will not only make you and your team more efficient when an incident arises, but they’ll also give you crucial feedback that you can use to tweak and improve your plan of action.

Implementing real-time monitoring and alerting for anomalous behavior, such as unusual API traffic, bulk data access, and login spikes, can help you identify threats before they escalate to major issues. Train your team to keep detailed audit logs. This way, you can trace what happened, when it occurred, and the extent of the breach with ease.

Responsible companies have a clear, pre-drafted communication plan in place for when things go wrong. Teams need to know the exact steps to take to contain the breach. However, it’s equally important to know how you’ll communicate the issue to affected users and regulators.

8. Stay Current with Platform Requirements and Regulations

Companies should know their obligations under relevant privacy laws, such as the EU’s General Data Protection Regulation (GDPR), the California Consumer Privacy Act (CCPA), and other emerging state-level regulations. However, that’s not always enough.

The App Store and Google Play Store are also constantly updating their security requirements and policies regarding data collection, encryption, permissions, and privacy. Apps that don’t meet the newest standards risk getting removed from the platforms.

Developers can stay ahead of industry threats by monitoring cybersecurity news and reports. This can help teams determine the best course of action against emerging threats, malware, and other security risks targeting mobile devices.

Keeping Users Safe Long Term

Mobile app security needs to be taken seriously. Cybercriminals and hackers are always looking for new ways to exploit loopholes and weaknesses in an app’s infrastructure to gain unauthorized access to sensitive data. Companies that leave data protection until the last minute or treat it as a one-time project open themselves and their users up to significant risk and exposure.

The truth is, data protection is an ongoing process. To stay ahead of hackers, you must constantly evaluate and test known threats while anticipating new attack methods on the horizon. Developers should use secure coding practices, strengthen authentication systems, protect APIs, and plan for the worst to stay one step ahead of attackers.

Data security can be the difference between a company that thrives and expands and one that falls victim to preventable attacks and must answer to regulators. Companies that treat user data protection as a core product commitment instead of a box to tick build stronger reputations and earn the long-term trust of their users.

About the Author

Hannah Hicklen Content Marketing Manager at Clutch

Hannah Hicklen is a content marketing manager who focuses on creating newsworthy content around tech services, such as software and web development, AI, and cybersecurity. With a background in SEO and editorial content, she now specializes in creating multi-channel marketing strategies that drive engagement, build brand authority, and generate high-quality leads. Hannah leverages data-driven insights and industry trends to craft compelling narratives that resonate with technical and non-technical audiences alike. 

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