Mobile App Security: What Every Business Owner Should Know Before You Ship
· 6 min read · Mona Technologies
Most mobile app security incidents you read about didn't come from a sophisticated attack. They came from something boring: an API key left inside the app's code, user data stored on the device without encryption, or a login screen that never checked who was actually asking. If you're a founder or product owner, you don't need to understand cryptography - you need to know which questions to ask your development team, and which answers should worry you.
Your app's code is not a secret
Anyone can download your app from the App Store or Google Play and decompile it in minutes with free tools. That means anything hardcoded into the app - API keys, admin credentials, backend URLs, encryption keys - is effectively public. This is one of the most common findings in mobile audits and it's called out directly in OWASP's Mobile Application Security project as a recurring category of risk (insecure data storage and insufficient cryptography both touch this). The fix isn't complicated: secrets belong on your server, not in the app package, and the app should only ever talk to your backend through short-lived, revocable tokens.
- Ask your dev team directly: 'Are there any API keys, passwords, or secret URLs hardcoded in the app?'
- Payment processing, admin functions, and anything involving other users' data should require a fresh authorization check on your server every time - not just trust the app.
- If your team can't explain how a leaked copy of the app binary would be handled, that's a gap worth closing before launch.
Data in transit and data at rest are two different problems
Your app talks to your servers constantly - login, checkout, syncing user data. That connection needs to be encrypted (HTTPS/TLS), full stop. Apple enforces this by default through App Transport Security, which blocks plaintext HTTP connections unless a developer explicitly opts out with a documented justification, and Google Play requires developers to disclose in the Data Safety section whether all collected user data is encrypted in transit. If your app has an ATS exception configured, or if your team can't say whether encryption-in-transit is 'yes' with confidence, get that answered before you ship an update - it also affects what your Play Store listing tells users about your app's practices.
Data at rest is a separate problem: anything stored locally on the phone - cached user info, saved passwords, session tokens, offline order data - needs its own protection, because a lost or stolen device, or a jailbroken one, bypasses network security entirely.
- Confirm every network call in the app uses HTTPS - no exceptions without a written reason.
- Ask what happens to cached data if a customer's phone is lost, stolen, or resold.
- Session tokens should expire and be revocable from your side, not live forever on the device.
Authentication is where most real damage happens
OWASP's 2024 Mobile Top 10 update moved 'Improper Credential Usage' and 'Insecure Authentication/Authorization' to the top of the list, ahead of categories that used to dominate, like insecure data storage. In plain terms: attackers increasingly target how your app proves who a user is, not just where data sits. For a business, this shows up as account takeover, coupon or loyalty-point abuse, or someone else's order history showing up in a customer's app.
- Every sensitive action (checkout, account changes, viewing other users' data) should re-verify identity server-side, not just check a locally stored flag.
- If you support 'remember me' or biometric login, ask exactly what's stored on the device to make that work and whether it can be reused if the device is compromised.
- Rate-limit login attempts and password resets - these remain one of the simplest, most abused entry points.
Third-party SDKs are part of your attack surface, not free features
Every analytics SDK, ad network, crash reporter, or payment plugin you add runs inside your app with roughly the same access your own code has. OWASP's 2024 list added 'Inadequate Supply Chain Security' as a distinct risk category specifically because of this - a vulnerable or over-permissioned third-party library becomes your vulnerability. Before approving a new SDK, it's reasonable to ask what data it collects, whether that's disclosed in your Play Store data safety form and App Store privacy label, and whether it's actually necessary.
The short version
You don't need to become a security expert - you need to ask your development team three things before every release: where secrets are stored, whether all data is encrypted in transit and at rest, and how identity is re-verified for sensitive actions. If those three answers are solid, you've closed off the vast majority of real-world mobile app security incidents. If any answer is vague, that's the gap to fix before launch, not after.