Mobile Security

Mobile Game Security

Overview

This skill covers mobile security resources from the awesome-game-security collection, focusing on Android and iOS game security research, reverse engineering, and protection bypass techniques.

Android Security

APK Analysis

Tools

• apktool: Decompile/recompile APKs
• jadx: DEX to Java decompiler
• APKiD: Identify packers/protectors
• Frida: Dynamic instrumentation
• APKLab: VS Code integration

Workflow

# Decompile APK
apktool d game.apk

# Analyze DEX files
jadx -d output game.apk

# Identify protection
apkid game.apk

Native Library Analysis

IL2CPP Games (Unity)

1. Extract libil2cpp.so from APK
2. Use IL2CPP Dumper to generate headers
3. Analyze with IDA/Ghidra
4. Hook using Frida or native hooks

Native Games

1. Identify target libraries (.so files)
2. Analyze with reverse engineering tools
3. Pattern scan for functions
4. Apply hooks/patches

Memory Manipulation

Tools

• GameGuardian: Memory editor
• Cheat Engine (ceserver): Remote debugging
• Custom memory tools: Direct /proc/pid/mem access

Access Methods

// Via /proc filesystem
int fd = open("/proc/pid/mem", O_RDWR);
pread64(fd, buffer, size, address);
pwrite64(fd, buffer, size, address);

Hooking Frameworks

Frida

// Basic function hook
Interceptor.attach(Module.findExportByName("libgame.so", "function_name"), {
    onEnter: function(args) {
        console.log("Called with: " + args[0]);
    },
    onLeave: function(retval) {
        retval.replace(0);
    }
});

Native Hooks

• Substrate: Inline hooking framework
• And64InlineHook: ARM64 inline hooks
• xHook: PLT hook library
• Dobby: Multi-platform hook framework

Root Detection Bypass

Common Checks

- /system/bin/su existence
- /system/xbin/su existence  
- Build.TAGS contains "test-keys"
- ro.build.selinux property
- Magisk files/folders
- Package manager checks

Bypass Methods

• Magisk Hide: Built-in root hiding
• LSPosed/EdXposed: Xposed framework hooks
• Frida scripts: Hook detection functions
• APK patching: Remove detection code

Zygisk Modules

// Zygisk module structure
class Module : public zygisk::ModuleBase {
    void onLoad(zygisk::Api *api, JNIEnv *env) override {
        this->api = api;
        this->env = env;
    }
    
    void preAppSpecialize(zygisk::AppSpecializeArgs *args) override {
        // Before app loads
    }
    
    void postAppSpecialize(const zygisk::AppSpecializeArgs *args) override {
        // After app loads - inject here
    }
};

Android Protections

Common Protectors

• Tencent ACE: Chinese market protection
• AppSealing: Commercial protection
• DexGuard/ProGuard: Obfuscation
• Arxan: Enterprise protection

iOS Security

Analysis Tools

• Hopper: Disassembler
• IDA Pro: Industry standard
• class-dump: Objective-C header extraction
• Frida: Dynamic instrumentation
• Clutch/dumpdecrypted: App decryption

Jailbreak Tools

• H5GG: iOS cheat engine
• Flex: Runtime patching
• Cycript: Runtime manipulation
• ceserver-ios: Cheat Engine for iOS

Hooking (Jailbroken)

// Using Logos (Theos)
%hook TargetClass
- (int)targetMethod:(int)arg {
    int result = %orig;
    return result * 2;  // Modify return
}
%end

Non-Jailbreak Techniques

• Sideloading: Modified IPAs
• Enterprise certificates: Custom signing
• AltStore: Self-signing tool

Unity Mobile Games

IL2CPP Analysis

1. Locate libil2cpp.so (Android) or UnityFramework (iOS)
2. Find global-metadata.dat
3. Run IL2CPPDumper
4. Generate SDK/headers
5. Hook target functions

Mono Analysis

1. Extract managed DLLs
2. Decompile with dnSpy/ILSpy
3. Modify and repackage
4. Or hook at runtime

Common Targets

- Currency/coins values
- Player stats (health, damage)
- Inventory manipulation
- Premium unlocks
- Ad removal

Unreal Mobile Games

Analysis Approach

1. Identify UE version
2. Dump SDK using appropriate tool
3. Locate GObjects, GNames
4. Find target functionality
5. Apply memory patches or hooks

Overlay Rendering (Android)

Surface-Based

// Native surface overlay
ANativeWindow* window = ANativeWindow_fromSurface(env, surface);
// Render using OpenGL ES or Vulkan

ImGui Integration

• Zygisk + ImGui modules
• Surface hijacking
• Direct framebuffer access

Network Analysis

Tools

• mitmproxy: MITM proxy
• Charles Proxy: Traffic analysis
• Frida SSL bypass: Certificate pinning bypass

Certificate Pinning Bypass

// Frida universal SSL bypass
Java.perform(function() {
    var TrustManager = Java.registerClass({
        implements: [X509TrustManager],
        methods: {
            checkClientTrusted: function() {},
            checkServerTrusted: function() {},
            getAcceptedIssuers: function() { return []; }
        }
    });
    // Install custom TrustManager
});

Anti-Cheat on Mobile

Common Systems

• Tencent ACE: Chinese games
• NetEase Protection: NetEase games
• Custom solutions: Per-game implementations

Detection Methods

- Root/jailbreak detection
- Frida detection
- Emulator detection
- Integrity checks
- Debugger detection
- Hook detection

Bypass Strategies

1. Static analysis of detection code
2. Hook detection functions
3. Hide injection footprint
4. Timing attack consideration
5. Clean environment emulation

Emulator Considerations

Android Emulators

• LDPlayer: Gaming focused
• BlueStacks: Popular emulator
• NoxPlayer: Game optimization
• MEmu: Android gaming

Emulator Detection

- Build.FINGERPRINT checks
- Hardware sensor verification
- File system characteristics
- Performance timing

Resource Organization

The README contains:

• Android hooking frameworks
• iOS jailbreak tools
• Memory manipulation utilities
• Root/jailbreak bypass tools
• Mobile anti-cheat research
• Emulator resources