Top 5 Vulnerabilities Found in Mobile App Security Tests
With mobile apps becoming an essential part of daily life from banking and shopping to healthcare and entertainment securing them is no longer optional. Every day, sensitive data is exchanged through mobile apps, making them a prime target for cybercriminals. Yet, many developers still overlook core security principles, leading to vulnerabilities that can compromise user data, brand reputation, and business operations.
Insecure Data Storage
One of the most common and dangerous issues discovered in mobile app security testing is insecure data storage. Many mobile apps store sensitive user information—like credentials, personal data, payment information, session tokens, or health records—on the device itself. When this data is not encrypted or securely protected, it becomes easy prey for attackers, especially on rooted or jailbroken devices. Insecure storage often stems from developers relying on local databases, shared preferences, or unprotected files without using encryption. In Android, for instance, data saved in Shared Preferences or SQLite databases can be easily extracted if not encrypted. Similarly, iOS apps sometimes store data in the keychain or user defaults without implementing proper protections.an attacker with physical access to the device or using malware can access this unprotected data. Worse, mobile backup files or debug logs might also contain sensitive data unintentionally, which can be retrieved and analyzed during forensic investigation.
Insecure Communication
Another top vulnerability involves insecure communication between the mobile app and backend servers. Many apps transmit sensitive data like login credentials, payment details, or API tokens over the internet. If this data is not encrypted or validated properly, it can be intercepted or manipulated by attackers using man-in-the-middle (MITM) attacks. Even when HTTPS is used, some apps fail to validate SSL/TLS certificates properly. This can allow attackers to present fake certificates and still intercept traffic. The problem gets worse on rooted or jailbroken devices where network traffic can be easily inspected using tools like Burp Suite or Wireshark. Security testers often find mobile apps leaking session IDs, tokens, or sensitive data over unencrypted channels or weakly configured HTTPS implementations. This opens up possibilities for session hijacking, credential theft, or data tampering.
Improper Authentication and Authorization
Authentication and authorization flaws continue to be significant risks in mobile apps. These vulnerabilities occur when apps fail to properly verify a user’s identity or do not enforce access controls on user actions or data. One common issue is storing authentication tokens insecurely, or relying on client-side mechanisms for access control. If tokens are predictable or easily extractable, attackers can impersonate users or escalate privileges. In some cases, mobile apps allow users to perform functions without verifying session tokens against the server. This opens the door to impersonation or privilege escalation attacks. Another problem arises from weak or missing input validation on the backend. For instance, an attacker might change a user ID in a request to access another user’s profile, a classic example of Insecure Direct Object Reference (IDOR).
Reverse Engineering and Code Tampering
Mobile apps are distributed as packaged code—APK files for Android and IPA files for iOS—which means determined attackers can decompile and analyze them. Without proper obfuscation, the code reveals sensitive logic, hardcoded secrets, API keys, or proprietary algorithms. This makes it easier for attackers to tamper with the app, inject malicious behavior, or develop counterfeit apps. During testing, security analysts often find hardcoded secrets, debug logs, or exposed APIs within the app code. Sometimes, test credentials, Firebase keys, or encryption keys are embedded in the code without protection. These can be extracted using tools like JADX, Apktool, or Hopper, allowing attackers to perform deeper exploitation or modify the app behavior. Tampering also includes altering the app to bypass security checks, like removing root detection logic, disabling certificate pinning, or injecting malware into legitimate apps to launch attacks on users
Insufficient Protection Against Runtime Attacks
While many developers focus on securing static code, runtime protections are often overlooked. Runtime attacks exploit apps during their execution, particularly on rooted or jailbroken devices where attackers can modify memory, bypass security checks, or inject malicious code. Common issues include lack of root/jailbreak detection, absence of debugging detection, or failing to check for emulators. Attackers can run apps in modified environments to bypass security mechanisms, intercept sensitive data, or exploit internal functionality. Some apps also expose internal components, such as exported Android activities, services, or broadcast receivers, which can be triggered by malicious apps on the same device. During testing, analysts often find that apps do not prevent runtime debugging or fail to detect when the execution environment has been compromised. This makes it easier for attackers to manipulate the app or access internal data during use.