Android Anti Instrumentation Bypass

Android Anti-Instrumentation & SSL Pinning Bypass

A practical workflow to bypass Android app protections that detect instrumentation, root, or enforce TLS pinning. Focuses on fast triage, common detections, and copy-pasteable hooks.

Quick Start

# Attach to running app (avoids spawn-time detection)
frida -U -n com.example.app

# Spawn with anti-detection script
frida -U -f com.example.app -l anti-frida-detection.js

# List processes
frida-ps -Uai

Detection Surface (What Apps Check)

Step 1: Quick Wins (30 Seconds)

Hide Root with Magisk DenyList

# In Magisk app:
# 1. Enable Zygisk
# 2. Enable DenyList
# 3. Add target package
# 4. Reboot and retest

Many apps only check for obvious indicators. DenyList often neutralizes naive checks.

Try Frida Codeshare Scripts

# Common drop-in scripts
frida -U -f com.example.app -l anti-frida-detection.js
frida -U -f com.example.app -l anti-root-bypass.js
frida -U -f com.example.app -l hide_frida_gum.js

Codeshare: https://codeshare.frida.re/

Use Medusa Framework

Medusa provides 90+ ready-made modules:

git clone https://github.com/Ch0pin/medusa
cd medusa
pip install -r requirements.txt
python medusa.py

# Interactive workflow
show categories
use http_communications/multiple_unpinner
use root_detection/universal_root_detection_bypass
run com.target.app

Step 2: Attach Late to Avoid Init-Time Detection

Many detections only run during process spawn. Attach after UI loads:

# Launch app normally, wait for UI, then attach
frida -U -n com.example.app

# Or with Objection gadget
objection --gadget com.example.app explore

Step 3: Map Detection Logic (Static Analysis)

Search Jadx for keywords: frida, gum, root, magisk, ptrace, su, getprop, debugger

Common Java APIs to hook:

• android.os.Debug.isDebuggerConnected
• android.app.ActivityManager.getRunningAppProcesses
• android.app.ActivityManager.getRunningServices
• java.lang.System.loadLibrary
• android.os.SystemProperties.get

Step 4: Runtime Stubbing with Frida

Basic Anti-Frida Bypass

Java.perform(() => {
  // Neutralize debugger checks
  const Debug = Java.use('android.os.Debug');
  Debug.isDebuggerConnected.implementation = function() { return false; };

  // Kill ActivityManager scans
  const AM = Java.use('android.app.ActivityManager');
  AM.getRunningAppProcesses.implementation = function() {
    return java.util.Collections.emptyList();
  };
  AM.getRunningServices.implementation = function() {
    return java.util.Collections.emptyList();
  };
});

Custom Detection Class Stubbing

Java.perform(() => {
  try {
    const Checks = Java.use('com.example.security.Checks');
    Checks.isFridaDetected.implementation = function() { return false; };
    Checks.isRooted.implementation = function() { return false; };
  } catch(e) {
    console.log('Custom check class not found');
  }
});

Log Suspicious Methods

Java.perform(() => {
  const Det = Java.use('com.example.security.DetectionManager');
  Det.checkFrida.implementation = function() {
    console.log('[+] checkFrida() called');
    return false;
  };
});

Dump Classes on Crash

Java.perform(() => {
  Java.enumerateLoadedClasses({
    onMatch: n => console.log(n),
    onComplete: () => console.log('Done')
  });
});

Step 5: Bypass Emulator/VM Detection

Spoof Build Fields

Java.perform(function() {
  var Build = Java.use('android.os.Build');
  Build.MODEL.value = 'Pixel 7 Pro';
  Build.MANUFACTURER.value = 'Google';
  Build.BRAND.value = 'google';
  Build.FINGERPRINT.value = 'google/panther/panther:14/UP1A.231105.003/1234567:user/release-keys';
  Build.HARDWARE.value = 'panther';
});

Spoof Device Identifiers

Java.perform(function() {
  // TelephonyManager
  var TelephonyManager = Java.use('android.telephony.TelephonyManager');
  TelephonyManager.getDeviceId.implementation = function() { return '123456789012345'; };
  TelephonyManager.getSubscriberId.implementation = function() { return '123456789012345'; };
  
  // WiFi MAC
  var WifiInfo = Java.use('android.net.wifi.WifiInfo');
  WifiInfo.getMacAddress.implementation = function() { return '02:00:00:12:34:56'; };
});

Step 6: SSL Pinning Bypass

Basic SSLContext Hook

Java.perform(function() {
  var X509TrustManager = Java.use('javax.net.ssl.X509TrustManager');
  var SSLContext = Java.use('javax.net.ssl.SSLContext');

  // No-op validations
  X509TrustManager.checkClientTrusted.implementation = function() {};
  X509TrustManager.checkServerTrusted.implementation = function() {};

  // Force permissive TrustManagers
  var TrustManagers = [X509TrustManager.$new()];
  var SSLContextInit = SSLContext.init.overload(
    '[Ljavax.net.ssl.KeyManager',
    '[Ljavax.net.ssl.TrustManager',
    'java.security.SecureRandom'
  );
  SSLContextInit.implementation = function(km, tm, sr) {
    return SSLContextInit.call(this, km, TrustManagers, sr);
  };
});

OkHttp4 / Cronet Pinning (2024+)

Java.perform(() => {
  try {
    const Pinner = Java.use('okhttp3.CertificatePinner');
    Pinner.check.overload('java.lang.String', 'java.util.List').implementation = function() {};
    Pinner.check$okhttp.implementation = function() {};
  } catch(e) {}

  try {
    const CronetB = Java.use('org.chromium.net.CronetEngine$Builder');
    CronetB.enablePublicKeyPinningBypassForLocalTrustAnchors.overload('boolean').implementation = function() { return this; };
    CronetB.setPublicKeyPins.overload('java.lang.String', 'java.lang.Set', 'boolean').implementation = function() { return this; };
  } catch(e) {}
});

Native BoringSSL Hook (for gRPC/Cronet)

const customVerify = Module.findExportByName(null, 'SSL_CTX_set_custom_verify');
if (customVerify) {
  Interceptor.attach(customVerify, {
    onEnter(args) {
      args[1] = ptr(0); // SSL_VERIFY_NONE
      args[2] = NULL;   // disable callback
    }
  });
}

Step 7: Native Detection Bypass

Trace JNI Entry Points

frida-trace -n com.example.app -i "JNI_OnLoad"

Neuter ptrace (Anti-Debug)

const ptrace = Module.findExportByName(null, 'ptrace');
if (ptrace) {
  Interceptor.replace(ptrace, new NativeCallback(function() {
    return -1; // pretend failure
  }, 'int', ['int', 'int', 'pointer', 'pointer']));
}

Scan Native Libraries

# List exported symbols & JNI
nm -D libfoo.so | head
objdump -T libfoo.so | grep Java_
strings -n 6 libfoo.so | egrep -i 'frida|ptrace|gum|magisk|su|root'

Step 8: Stealth Frida Server (phantom-frida)

For apps that detect Frida fingerprints, use phantom-frida:

python3 build.py --version 17.7.2 --name myserver --port 27142 --extended --verify
adb push output/myserver-server-17.7.2-android-arm64 /data/local/tmp/myserver-server
adb shell chmod 755 /data/local/tmp/myserver-server
adb shell /data/local/tmp/myserver-server -D &
adb forward tcp:27142 tcp:27142
frida -H 127.0.0.1:27142 -f com.example.app

phantom-frida: https://github.com/TheQmaks/phantom-frida

Step 9: Universal Proxy + TLS Unpinning

Use HTTP Toolkit hooks for comprehensive unpinning + proxy forcing:

# Download hooks from https://github.com/httptoolkit/frida-interception-and-unpinning
frida -U -f com.vendor.app \
  -l ./android-unpinning-with-proxy.js \
  --no-pause

# mitmproxy listening locally
mitmproxy -p 8080

Step 10: Static TLS Pinning Removal (Fallback)

apk-mitm app.apk
# Install patched APK and proxy via Burp/mitmproxy

apk-mitm: https://github.com/shroudedcode/apk-mitm

Objection Patching

objection patchapk --source app.apk

Requires apktool. Gadget injection enables instrumentation without root.

Command Cheat Sheet

# List processes
frida-ps -Uai

# Attach to running app
frida -U -n com.example.app

# Spawn with script
frida -U -f com.example.app -l script.js

# Trace native
frida-trace -n com.example.app -i "JNI_OnLoad"

# Objection runtime
objection --gadget com.example.app explore

# Static TLS removal
apk-mitm app.apk

Troubleshooting

References

• Frida Codeshare: https://codeshare.frida.re/
• Objection: https://github.com/sensepost/objection
• Medusa: https://github.com/Ch0pin/medusa
• phantom-frida: https://github.com/TheQmaks/phantom-frida
• HTTP Toolkit Hooks: https://github.com/httptoolkit/frida-interception-and-unpinning
• apk-mitm: https://github.com/shroudedcode/apk-mitm
• Jadx: https://github.com/skylot/jadx
• Ghidra: https://ghidra-sre.org/
• Magisk: https://github.com/topjohnwu/Magisk