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name, description, version, platforms, triggers, depends_on, metadata
name description version platforms triggers depends_on metadata
reverse-engineering-mobile Use for mobile app reverse engineering: Android APK analysis, iOS IPA analysis, dex/smali reversing, native library (.so) analysis, keychain/keystore extraction, SSL pinning bypass, root:REDACTED detection bypass, and mobile app security research. 1.0.0
linux
macos
windows
reverse
engineering
mobile
app
android
apk
analysis
ios
ipa
dex
smali
reversing
tags
reverse
engineering
mobile

Reverse Engineering — Mobile Applications

Trigger Conditions

  • Android APK decompilation and analysis
  • iOS IPA analysis and decryption
  • DEX/Smali code analysis and modification
  • Native library (.so / .dylib) reversing
  • SSL/TLS pinning bypass
  • root:REDACTED detection bypass
  • Keychain/Keystore data extraction
  • Mobile API traffic analysis
  • App sandbox exploration
  • Mobile cryptography analysis
  • Frida script development for mobile
  • Obfuscated mobile app analysis
  • React Native / Flutter / Unity app reversing
  • Mobile game modification

Core Methodology

1. Android APK Analysis

Decompilation pipeline:

# 1. Extract APK
adb shell pm path com.target.app
adb pull /data/app/.../base.apk

# 2. Decompile with JADX (Java source)
jadx -d output --deobf --deobf-min 3 base.apk

# 3. Decompile with apktool (resources + smali)
apktool d base.apk -o apktool_output

# 4. Analyze manifest
cat apktool_output/AndroidManifest.xml
# Look for: exported activities, permissions, deep links, providers

# 5. Search for API endpoints
grep -rE 'https?://' output/ --include='*.java' | \
  grep -v '\.xml' | sort -u

# 6. Search for crypto keys/secrets
grep -rE '(api_key|secret|password|token|AES|RSA)' output/ --include='*.java'

# 7. Analyze native libraries
unzip base.apk 'lib/*'
file lib/arm64-v8a/*.so
# Reverse with IDA/Ghidra

Smali modification:

# Bypass root detection:
# Original:
invoke-static {}, Lcom/target/RootDetector;->isRooted()Z
move-result v0
if-eqz v0, :cond_not_rooted

# Patched:
const/4 v0, 0x0  # always return false

# Bypass SSL pinning:
# Find the pinning class, override the check method
.method public verify(Ljava/lang/String;Ljava/security/cert/X509Certificate;)Z
    .registers 3
    const/4 v0, 0x1
    return v0
.end method

Rebuild and sign:

# Rebuild with apktool
apktool b apktool_output -o modified.apk

# Sign with uber-apk-signer
java -jar uber-apk-signer.jar -a modified.apk

# Or with apksigner (Android SDK)
apksigner sign --ks my.keystore modified.apk

2. iOS IPA Analysis

IPA extraction:

# Extract IPA (from jailbroken device or decrypted dump)
unzip TargetApp.ipa -d ipa_output

# Analyze binary
file Payload/TargetApp.app/TargetApp
otool -l Payload/TargetApp.app/TargetApp    # load commands
otool -Iv Payload/TargetApp.app/TargetApp   # imports
strings Payload/TargetApp.app/TargetApp | head -100

# Class-dump (Objective-C headers)
class-dump Payload/TargetApp.app/TargetApp > headers.txt

# Hopper Disassembler or IDA for full analysis
# Ghidra also supports Mach-O

Frida on iOS:

# Install Frida on jailbroken device
# List processes
frida-ps -U

# Attach to app
frida -U -f com.target.app --no-pause

# Script — bypass SSL pinning
frida -U -f com.target.app --no-pause -l ssl_bypass.js

3. SSL Pinning Bypass

Android — Frida universal bypass:

// ssl_pinning_bypass.js
Java.perform(function() {
    // OkHttp 3
    try {
        var CertificatePinner = Java.use('okhttp3.CertificatePinner');
        CertificatePinner.check.overload('java.lang.String', 'java.util.List').implementation = function() {};
        CertificatePinner.check.overload('java.lang.String', 'java.security.cert.Certificate').implementation = function() {};
    } catch(e) {}

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

    var TrustManagerFactory = Java.use('javax.net.ssl.TrustManagerFactory');
    var tmf = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
    tmf.init(null);
    var trustManagers = tmf.getTrustManagers();
    // Replace with our trust manager
});

// iOS — bypass
var SSLKillSwitch = ObjC.classes.NSURLSession;
// Or hook SecTrustEvaluate:
Interceptor.attach(
    Module.findExportByName('Security', 'SecTrustEvaluate'), {
        onLeave: function(retval) {
            retval.replace(0);  // errSecSuccess
        }
    }
);

Android — network security config:

<!-- Create res/xml/network_security_config.xml -->
<network-security-config>
    <base-config>
        <trust-anchors>
            <certificates src="system" />
            <certificates src="user" />
        </trust-anchors>
    </base-config>
    <debug-overrides>
        <trust-anchors>
            <certificates src="user" />
        </trust-anchors>
    </debug-overrides>
</network-security-config>

4. root:REDACTED Detection Bypass

Android — common detection methods:

// Detection checks to bypass:
// 1. Check for su binary
Runtime.getRuntime().exec("which su")

// 2. Check for Superuser.apk
new File("/system/app/Superuser.apk").exists()

// 3. Check build tags
Build.TAGS.contains("test-keys")

// 4. Check for Magisk
new File("/sbin/.magisk").exists()

// 5. Check for dangerous properties
System.getProperty("ro.build.selinux")

// Frida bypass:
Java.perform(function() {
    // Hook all detection methods
    var RootBeer = Java.use('com.scottyab.rootbeer.RootBeer');
    RootBeer.isRooted.implementation = function() { return false; };

    // Hook file existence checks
    var File = Java.use('java.io.File');
    File.exists.implementation = function() {
        var path = this.getAbsolutePath();
        if (path.indexOf("su") >= 0 || path.indexOf("magisk") >= 0) {
            return false;
        }
        return this.exists();
    };
});

5. Native Library (.so) Analysis

Extraction and analysis:

# Extract from APK
unzip app.apk 'lib/*'

# Analyze with Ghidra/IDA
ghidraRun
# Load .so file, set base address, analyze

# Or with radare2
r2 lib/arm64-v8a/libnative.so
aaa
afl
pdf @ main

# Identify JNI functions (Java_ prefix)
strings libnative.so | grep "^Java_"

JNI function naming:

Java_{package_name}_{class_name}_{method_name}
Example: Java_com_target_app_crypto_NativeLib_encrypt

// JNI signature:
JNIEXPORT jstring JNICALL
Java_com_target_app_crypto_NativeLib_encrypt(
    JNIEnv *env,
    jobject thiz,
    jstring input
);

Frida — hook native function:

// Find exported function
var encryptFunc = Module.findExportByName('libnative.so', 'Java_com_target_encrypt');
Interceptor.attach(encryptFunc, {
    onEnter: function(args) {
        // args[0] = JNIEnv*, args[1] = jobject, args[2] = jstring
        var input = Java.vm.getEnv().getStringUtfChars(args[2], null).readCString();
        console.log('encrypt input:', input);
    },
    onLeave: function(retval) {
        var result = Java.vm.getEnv().getStringUtfChars(retval, null).readCString();
        console.log('encrypt output:', result);
    }
});

6. Keychain/Keystore Extraction

Android KeyStore:

# Requires root
adb root
adb shell
su

# KeyStore files
ls /data/misc/keystore/
ls /data/system/locksettings/

# Shared preferences (often contain tokens)
ls /data/data/com.target.app/shared_prefs/
cat /data/data/com.target.app/shared_prefs/*.xml

# SQLite databases
ls /data/data/com.target.app/databases/
sqlite3 /data/data/com.target.app/databases/*.db ".tables"

iOS Keychain:

# Requires jailbreak
# Keychain-Dumper
./keychain_dumper -a    # all entries
./keychain_dumper -g    # generic passwords
./keychain_dumper -i    # internet passwords

# Or with Frida
frida -U SpringBoard -l keychain_dump.js

7. Framework-Specific Analysis

React Native:

# JS bundle extraction
unzip app.apk 'assets/index.android.bundle'
# Deobfuscate
# Look for fetch/axios calls in bundle

# Native modules
grep -r 'ReactMethod' android/

Flutter:

# Flutter apps have libapp.so (AOT compiled)
# Extract and analyze with Ghidra
# Flutter symbols are preserved in debug builds
unzip app.apk 'lib/*/libapp.so'

# For JIT builds, look at kernel_blob.bin
unzip app.apk 'assets/flutter_assets/kernel_blob.bin'

Unity:

# Extract assets
unzip app.apk 'assets/bin/Data/*'

# Decompile with Il2CppDumper
# Dump IL2CPP metadata
Il2CppDumper.exe assets/bin/Data/Managed/Metadata/global-metadata.dat \
  lib/arm64-v8a/libil2cpp.so output/

# Results: script.json (method names), dump.cs (C# stubs)

Implementation Standards

  • All mobile RE produces working modifications or analysis
  • Provide both static and dynamic analysis approaches
  • Include Frida scripts for common bypasses
  • Document app architecture and data flow
  • No partial analysis — complete or nothing

Output Format

For mobile RE tasks:

  1. App Identification — platform, framework, version, protections
  2. Static Analysis — decompiled code, strings, API endpoints, crypto
  3. Dynamic Analysis — traffic, behavior, Frida hooks
  4. Security Mechanisms — pinning, root detection, obfuscation
  5. Bypass Methods — working patches, Frida scripts, modified APKs
  6. Data Extraction — stored credentials, tokens, keys

Всё, брат.

Related

  • skill android-forensics — форензика
  • skill reverse-engineering-binary — native libs
  • skill web-exploitation — API реверс