The essentials
85% of mobile apps have at least one critical vulnerability according to the OWASP Mobile Top 10 2024. The average cost of a data breach reaches $4.45 million according to IBM Security, and GDPR fines can reach 4% of global revenue. A targeted mobile security audit costs between €3,000 and €15,000: a small investment against these risks.
Mobile security, a critical issue in 2026
Mobile apps have become the main digital entry point for billions of users. Banking, health, e-commerce, messaging: we entrust our most sensitive data to our smartphones. Yet according to the OWASP Mobile Top 10 2024 report, 85% of mobile apps have at least one critical vulnerability.
For businesses, the consequences of a security flaw are severe: customer data leaks, GDPR fines (up to 4% of global revenue), reputational damage, even legal liability. In 2023, the average cost of a data breach reached $4.45 million according to IBM Security.
Most incidents don’t come from sophisticated attacks: they come from default configurations, forgotten dependencies, overly broad permissions and secrets left in the code. A serious audit starts by eliminating these blind spots, well before any conversation about advanced cryptography.
The 10 most common mobile security flaws
1. Insecure data storage
Sensitive information (tokens, passwords, personal data) is stored unencrypted on the device, accessible to any malicious app or in case of theft.
Solutions: use the Keychain (iOS) or EncryptedSharedPreferences (Android), encrypt local databases with SQLCipher, never log sensitive information even in development.
2. Insecure network communication
Data travels unencrypted between the app and the server, enabling Man-in-the-Middle attacks where an attacker intercepts and alters communications.
Solutions: enforce HTTPS for all communications, implement certificate pinning, use TLS 1.3 at minimum, only send sensitive data in POST request bodies.
3. Weak authentication and session management
Weak mechanisms let attackers take over user accounts or keep sessions active indefinitely.
Solutions: JWT tokens with short expiry (15-30 min) and refresh tokens, server-side session invalidation on logout, biometric authentication as a second factor, rate limiting on authentication endpoints.
4. Code injection and unvalidated input
The app accepts user input without validation, enabling malicious code injection (SQL, JavaScript, system commands).
Solutions: validate and sanitize all input on both client AND server, use prepared statements, encode output before rendering it in WebViews.
5. Use of vulnerable components
About 70% of apps contain at least one vulnerable dependency. Attackers specifically target published CVEs on third-party libraries that are never updated.
Solutions: regularly audit dependencies (npm audit, yarn audit), use Snyk, Dependabot or OWASP Dependency-Check, prefer actively maintained libraries.
6. No source code protection
The app’s code is easily decompiled, exposing business logic, API keys and proprietary algorithms.
Solutions: code obfuscation (ProGuard/R8 for Android, SwiftShield for iOS), never hardcode secrets, root/jailbreak detection.
7. Improper permission handling
The app requests excessive permissions or doesn’t properly handle permission denials.
Solutions: principle of least privilege, request permissions at the moment they’re needed (lazy permissions), clearly explain their purpose.
8. Flaws in inter-app communication
Inter-app communication mechanisms (Deep Links, Intents, URL Schemes) can be exploited to steal data or trigger unauthorized actions.
Solutions: strictly validate all data received via Deep Links, use App Links / Universal Links with domain verification, avoid the clipboard for sensitive data.
9. No detection of compromised environments
The app runs without checking whether the environment is safe (rooted/jailbroken devices, emulators, hooking frameworks like Frida or Xposed).
Solutions: root/jailbreak detection, app integrity checks, Google Play Integrity API or Apple DeviceCheck.
10. Poor cryptography practices
Use of outdated algorithms (MD5, SHA1, DES), hardcoded keys, predictable initialization vectors.
Solutions: modern, proven algorithms (AES-256-GCM, ChaCha20), keys generated with a secure cryptographic generator, storage in the Keychain/Keystore.
Security checklist for your mobile apps
| Area | Checkpoints |
|---|---|
| Storage | No sensitive data unencrypted, Keychain/Keystore used, no sensitive logs, encrypted local databases |
| Network | HTTPS mandatory, certificate pinning, TLS 1.2+ minimum, no sensitive data in URLs |
| Authentication | Short-lived tokens, server-side invalidation, brute-force protection, biometrics available |
| Code | Obfuscation enabled, no hardcoded secrets, audited dependencies, root/jailbreak detection |
| User input | Client AND server validation, prepared statements, output encoding in WebViews |
What an application security audit covers
A serious audit combines several complementary approaches: static code analysis (SAST), third-party dependency analysis, configuration review (cloud, servers, databases), penetration testing on exposed features, and a review of internal processes (secrets management, access rights, deployments). The final deliverable is a prioritized report with a realistic remediation plan, not an unreadable list of hundreds of alerts.
For projects handling data that must be protected long-term (legal archives, industrial secrets, medical records), integrating post-quantum cryptography algorithms (CRYSTALS-Kyber for key exchange, CRYSTALS-Dilithium for signatures) becomes an architecture decision to plan for, not a technical curiosity. That’s the approach we implemented on an event ticketing platform, signing each ticket with both a classical algorithm and Dilithium, for long-term protection with no compatibility break.
FAQ
Is my app really at risk even though my company is small?
Yes. According to Verizon, 43% of cyberattacks target small and medium businesses. Attackers use automated tools that scan thousands of apps looking for known vulnerabilities, regardless of company size.
How much does a mobile security audit cost?
A targeted audit starts around €3,000 - €4,500 (one app, a defined scope, a report with the top 10 vulnerabilities). A complete audit with penetration testing typically falls between €8,000 and €20,000 depending on system size and access granted.
Are cross-platform frameworks (React Native, Flutter) less secure than native?
Not inherently. Modern frameworks offer a good level of security by default. Vulnerabilities mainly come from poor development practices, not from the framework itself: the same security principles apply regardless of the technology chosen (see our PWA vs native comparison).
Where should I start to secure an existing app?
Four steps in order: audit dependencies (npm audit, free and fast), check local storage for unencrypted sensitive data, test network communications with a proxy (Charles, Burp), then consult an expert for a deeper audit if the initial results are concerning.
Neodigit: mobile apps secure by design
At Neodigit, security is built into your mobile apps from the design phase, not added as an afterthought. Our approach: security by design from the first lines of code, a modern stack (React Native) with security best practices, continuous dependency and code auditing, penetration testing before every release, GDPR compliance built into the architecture.
Have an existing app to audit or a new project to secure? Let’s talk.