Conducting Mobile App Penetration Test

Conducting Mobile App Penetration Test

When to Use

• Testing mobile applications before release to identify security vulnerabilities and data protection issues
• Conducting compliance assessments against OWASP MASVS (Mobile Application Security Verification Standard) levels L1 and L2
• Evaluating the security of mobile banking, healthcare, or government applications handling sensitive data
• Testing mobile apps that interact with backend APIs to assess the end-to-end security of the mobile ecosystem
• Assessing mobile application resistance to reverse engineering, tampering, and runtime manipulation

Do not use against mobile applications without written authorization from the application owner, for distributing modified or repackaged applications, or for testing apps on the public app stores without a separate test build.

Prerequisites

• Target application IPA (iOS) and APK (Android) files or access to download from a private distribution channel
• Rooted Android device or emulator (Genymotion, Android Studio AVD) with Frida, Objection, and Magisk installed
• Jailbroken iOS device or Corellium virtual device with Frida, Objection, and SSL Kill Switch installed
• Static analysis tools: jadx (Android decompilation), Hopper/Ghidra (iOS binary analysis), MobSF (automated scanning)
• Burp Suite Professional configured as proxy for intercepting mobile app traffic with CA certificate installed on the test device

Legal Notice: This skill is for authorized security testing and educational purposes only. Unauthorized use against systems you do not own or have written permission to test is illegal and may violate computer fraud laws.

Workflow

Step 1: Static Analysis

Analyze the application binary without executing it:

Android Static Analysis:

• Decompile the APK: jadx -d output/ target.apk to obtain Java/Kotlin source code
• Review AndroidManifest.xml for exported components (activities, services, receivers, content providers), permissions, and debuggable flag
• Search for hardcoded secrets: grep -rn "api_key\|password\|secret\|token\|aws_" output/
• Identify insecure data storage patterns: SharedPreferences with sensitive data, SQLite databases without encryption, files in external storage
• Check for WebView vulnerabilities: setJavaScriptEnabled(true), addJavascriptInterface(), and loading untrusted content
• Run MobSF automated scan: python manage.py runserver and upload the APK for automated static analysis

iOS Static Analysis:

• Extract the IPA and locate the Mach-O binary
• Use otool -L <binary> to list linked frameworks and identify third-party libraries
• Analyze with Ghidra or Hopper for hardcoded URLs, API endpoints, and embedded credentials
• Check Info.plist for App Transport Security (ATS) exceptions that allow insecure HTTP connections
• Review embedded entitlements for excessive capabilities

Step 2: Network Security Testing

Intercept and analyze all network communications:

• Configure Burp Suite as proxy on the test device and install the Burp CA certificate
• Exercise all application functionality while Burp captures API traffic
• SSL/TLS validation: Verify the app validates server certificates properly. If the app fails to connect through the proxy, it may implement certificate pinning.
• Certificate pinning bypass:
  • Android: Use Frida script: frida -U -f com.target.app -l ssl-pinning-bypass.js --no-pause
  • iOS: Use SSL Kill Switch or Objection: objection -g "Target App" explore --startup-command "ios sslpinning disable"
• API traffic analysis: Review all API calls for:
  • Sensitive data transmitted without encryption
  • Authentication tokens in URL parameters (visible in logs)
  • Excessive data in API responses beyond what the UI displays
  • Missing or weak authentication on API endpoints
• WebSocket and custom protocols: Check for non-HTTP communication channels that may bypass standard proxy interception

Step 3: Data Storage Analysis

Test for insecure local data storage:

Android Data Storage:

• Access app data directory: /data/data/com.target.app/
• Check SharedPreferences XML files for stored credentials, tokens, and PII
• Examine SQLite databases: sqlite3 /data/data/com.target.app/databases/*.db ".dump"
• Check for sensitive data in application logs: logcat -d | grep -i "password\|token\|key"
• Verify that application data is excluded from backups: android:allowBackup="false" in AndroidManifest.xml
• Check clipboard for sensitive data leakage

iOS Data Storage:

• Examine the Keychain for stored credentials: objection -g "Target App" explore then ios keychain dump
• Check NSUserDefaults/plist files: find /var/mobile/Containers/Data/Application/ -name "*.plist" -exec plutil -p {} \;
• Inspect SQLite databases and Core Data stores for unencrypted sensitive data
• Check for data leaking through screenshots (iOS captures screenshots during app backgrounding)
• Verify data protection class: sensitive files should use NSFileProtectionComplete

Step 4: Authentication and Session Management

Test mobile-specific authentication controls:

• Biometric bypass: Test if biometric authentication can be bypassed by hooking the authentication callback with Frida to always return success
• Token storage: Verify that authentication tokens are stored in the Keychain (iOS) or Android Keystore, not in SharedPreferences or files
• Session timeout: Verify that sessions expire after a reasonable idle timeout and that tokens are invalidated server-side on logout
• Root/jailbreak detection bypass: Test if the app detects rooted/jailbroken devices and if the detection can be bypassed with Frida or Magisk Hide
• Deep link abuse: Test if custom URL schemes or universal links can be used to bypass authentication or access restricted functionality