Is it possible to fully secure your mobile app?

TL;DR:

• No mobile app is 100% secure — if the device is in someone's hands, it can eventually be compromised.

• The real goal is to delay, detect and respond — make attacks expensive, catch them early, and wipe sensitive data before it leaks.

• Modern threats have shifted — supply-chain attacks, API exploitation and AI-powered vulnerability scanning are now as dangerous as reverse engineering.

• This article walks through practical hardening steps that every mobile developer should implement today.

Mobile security and data privacy is a topic emphasised by a growing number of business owners who want to assure their customers that their products are safe. So let's tackle the key question head-on:

Is it even possible to make your app 100% safe?

Securing your mobile app: it's never too much

A lot of developers have no idea how easy it is for hackers to extract data from their applications. They feel secure working on protected devices where each application is sandboxed. Many popular third-party libraries store plain-text tokens in the resource files of their demo apps, and developers copy this behaviour. The common practice is storing unencrypted keys or tokens in a seemingly safe data store provided by the operating-system API or in a local database. Is all of that enough to provide proper security? Unfortunately, not really.

Think like the attacker

One of the most effective ways to improve your app's security is to put yourself in the attacker's shoes. Whether through a formal penetration test or a hands-on workshop, attempting to bypass your own defences reveals weaknesses that code reviews alone will miss. When you work with the same tools that hackers use and see what they need to do to achieve their goal, your understanding of mobile app security increases dramatically.

Let's focus on the iOS app-cracking procedure as an example, though many of the concepts apply to Android as well.

Cracking the app

Official development tools are very useful for regular work, but they can give a lot of information to people hunting for data inside the app. otool, for instance, displays information about the libraries an app links against.

You can check which architectures they support or whether a library is properly signed. otool also reveals encryption information. On its own that is not a big deal. The keys are not public, so you cannot simply decrypt the binary. But you can crack the app when you have access to a jailbroken device.

No, I'm not going to give you detailed guidance on how to do that. But let's briefly run through the process.

Every application needs to be loaded into memory to run on the device. Before loading, it must be decrypted. With SSH access, the LLDB debugger (which has replaced the older GDB on Apple platforms) and the encryption information from otool, an attacker can run the app, attach the debugger and dump memory from the point where the application is loaded.

The next step is to replace the encrypted binary data with the unencrypted dump. The last thing is to change the flag that indicates app encryption. After that, you can use class-dump to extract all the headers (class names, properties and public methods). The whole process is not complicated, but it obviously requires terminal skills and technical knowledge about memory and the iOS system environment. Historically, a tool called Clutch automated this entire flow in a single command; today, Frida and its companion frida-ios-dump have largely replaced Clutch as the standard toolkit for runtime inspection and binary dumping.

With that information you can attach the application's process to a debugger and use Frida scripts (or the higher-level Objection toolkit) to make calls inside the application, hook methods, and inspect state at runtime. Older tools like Cycript and Snoop-it served a similar purpose, but Frida's cross-platform flexibility has made it the de facto standard for mobile security testing. With Objection you can explore an app's graphical structure, invoke methods, check the view hierarchy, list keychain items, and monitor network traffic and method invocations with their parameters.

A note on jailbreaks and rooting in 2025–2026: Public jailbreaks for modern iOS versions (iOS 17+) have become extremely rare. Apple's Pointer Authentication Codes (PAC) and Secure Page Tables have raised the bar significantly. That does not mean sophisticated attackers have stopped, state-sponsored groups and well-funded research teams still develop private exploits. On the Android side, rooting remains more accessible thanks to unlockable bootloaders and tools like Magisk, which means the Android attack surface is generally wider for runtime manipulation.

At this point, you may assume that there is no chance of fully securing your app. And you are right. A mobile application will never be 100% safe. The difference between server and mobile security is significant. To extract data from a server, you first need to gain access to it, which is the hardest part. On a mobile device, things are far simpler because the device is literally in the user's hands. This is why the main goal of mobile security is to detect that someone is tampering with the application, delay the attacker, and remove all sensitive data before it can be exfiltrated. Here are the key things you should consider to protect your app better.

How to play with an attacker? The rules of the game

• Use low-level APIs. For encryption, C-style functions are better than high-level APIs because they are much more complex and harder to replace with techniques such as method swizzling. It is also good to use inline functions or macros to make things more complicated for the attacker.

• Avoid storing keys, tokens or passwords in plain text. It does not matter if you plan to store them in the Info.plist, a separate file, or inside the app binary — always keep them encrypted and decrypt only at the moment of use.

• Use expiring tokens for authentication. Especially if you need to store them somewhere. Short-lived tokens limit the window of opportunity for an attacker.

• Implement certificate pinning properly. If the application sends sensitive data over a TLS connection, pin the server's Subject Public Key Info (SPKI) rather than the full certificate — this approach survives certificate rotation more gracefully. On Android, use Network Security Configuration to declare pins declaratively. On iOS, Apple provides Identity Pinning guidance and App Transport Security settings. Too often, users connect to open networks and ignore certificate warnings, accepting unauthorised certificates that let an attacker read traffic through a proxy.

• Clear sensitive data securely. Removing a file does not clear its data from the file system — it only deletes the reference. If you want to make sure data is truly gone, overwrite it with zeros or random bytes before unlinking the file. Consider applying this approach to database rows as well.

• Use obfuscation as part of a broader binary-protection strategy. Obfuscating class, protocol, property and method names makes reverse engineering significantly harder. On Android, R8 (the successor to ProGuard) handles code shrinking and obfuscation as part of the build pipeline. On iOS, commercial tools like iXGuard provide similar protection. You can also obfuscate tokens and API keys inside the binary to prevent them from being extracted as plain strings.

• Implement runtime integrity checks (not just jailbreak detection). Checking whether an app is running on a jailbroken or rooted device remains useful, but modern best practice goes further with Runtime Application Self-Protection (RASP). Combine multiple signals — file-system checks, process-level indicators, environment fingerprinting — rather than relying on a single condition. Solutions like Appdome and Promon can add these protections without modifying your source code.

• Detect debugger attachment. The application process has a flag that returns information about debugger connections, but do not rely on it alone. There are plenty of workarounds that can spoof this flag. Combine it with timing checks and other heuristics.

• Don't make your work obvious — play with the attacker. Create decoy methods with misleading names, for example -(BOOL)isDeviceJailbroken:(BOOL)jailbroken or -(BOOL)authenticateUser:(BOOL)auth. These honeypots can change encryption keys, delete user data or alert the server about the attack. When you detect tampering, it is better to subtly alter app behaviour than to crash or exit — the longer the attacker keeps trying, the more time you have to secure data.

• Check the keyboard cache. The keyboard cache can leak sensitive data in some cases. Exceptions where the cache is not used include:

• Secure text fields,

• Text fields with numbers-only input,

• Text fields with autocorrection disabled.

• Hide sensitive data on app switch. When entering the background, apps take screenshots to display in the app switcher. Consider hiding or blurring the content if your app handles sensitive data (for example, banking apps).

Modern threats you can't afford to ignore (2025–2026)

The threat landscape has evolved significantly since the early days of mobile security. Beyond reverse engineering and runtime attacks, here are the areas demanding attention today.

Supply-chain attacks

The OWASP Mobile Top 10 (2024) now ranks Inadequate Supply Chain Security as the #2 risk. A single compromised third-party SDK or library can expose every app that depends on it. Vet your dependencies carefully: audit their permissions, review their source code where possible, pin specific versions, and monitor for known vulnerabilities with tools like Dependabot or Snyk.

RASP (Runtime Application Self-Protection)

Traditional hardening (obfuscation, certificate pinning, jailbreak detection) is applied at build time. RASP goes further by monitoring the app at runtime and reacting to threats as they happen: detecting code injection, hooking attempts, debugger attachment, and environment tampering in real time. If you handle sensitive financial, health or personal data, RASP should be part of your security stack. Solutions like Appdome, Promon and Guardsquare's offerings provide RASP capabilities across both iOS and Android.

API security

Modern mobile apps are often thin clients that depend heavily on backend APIs. This means the API layer is a major attack surface. Insecure API endpoints, broken authentication, and excessive data exposure are consistently among the top mobile risks. Always enforce authentication and authorisation on the server side — never trust the client.

AI-powered threats

Attackers are increasingly using AI to automate vulnerability discovery, generate exploit code, and craft convincing phishing attacks. The barrier to entry for sophisticated attacks is dropping. On the defensive side, AI-driven security scanning can help you find issues before attackers do — but the arms race is real and accelerating.

Final word

Even combining every technique described above does not guarantee your data is safe. It prolongs and complicates the process of attacking your app. There is no way to make a mobile app as secure as a well-hardened server. The goal is defence in depth: layer multiple protections so that defeating one does not compromise the whole system.

When you detect an attack, clear sensitive data immediately and keep the attacker convinced they are still making progress. And remember that security is not a one-time task. Continuously test your app with updated tools and techniques, monitor the OWASP Mobile Top 10 for emerging risks, and treat security as an ongoing part of your development lifecycle, not a checkbox.