什麼是hook

所謂hook技術，就是通過一段程式碼(反射、代理)侵入到App啟動過程中，在原本執行的程式碼前插入其它的功能。比如：通過hook技術，上傳登陸頁面的賬號密碼等。

乾貨

對於主流hook框架（Xposed、Cydia Substrate），通常有以下三種方式來檢測一個App是否被hook:

• 安裝目錄中是否存在hook工具
• 儲存中是否存在hook安裝檔案
• 執行棧中是否存在hook相關類

1.查詢裝置安裝目錄中是否存在hook工具

private static boolean findHookAppName(Context context) {  
        PackageManager packageManager = context.getPackageManager();  
        List<ApplicationInfo> applicationInfoList = packageManager  
                .getInstalledApplications(PackageManager.GET_META_DATA);  
  
        for (ApplicationInfo applicationInfo : applicationInfoList) {  
            if (applicationInfo.packageName.equals("de.robv.android.xposed.installer")) {  
                Log.wtf("HookDetection", "Xposed found on the system.");  
                return true;  
            }  
            if (applicationInfo.packageName.equals("com.saurik.substrate")) {  
                Log.wtf("HookDetection", "Substrate found on the system.");  
                return true;  
            }  
        }  
        return false;  
    }  
 

2.查詢裝置儲存中是否存在hook安裝檔案

private static boolean findHookAppFile() {  
        try {  
            Set<String> libraries = new HashSet<String>();  
            String mapsFilename = "/proc/" + android.os.Process.myPid() + "/maps";  
            BufferedReader reader = new BufferedReader(new FileReader(mapsFilename));  
            String line;  
            while ((line = reader.readLine()) != null) {  
                if (line.endsWith(".so") || line.endsWith(".jar")) {  
                    int n = line.lastIndexOf(" ");  
                    libraries.add(line.substring(n + 1));  
                }  
            }  
            reader.close();  
            for (String library : libraries) {  
                if (library.contains("com.saurik.substrate")) {  
                    Log.wtf("HookDetection", "Substrate shared object found: " + library);  
                    return true;  
                }  
                if (library.contains("XposedBridge.jar")) {  
                    Log.wtf("HookDetection", "Xposed JAR found: " + library);  
                    return true;  
                }  
            }  
        } catch (Exception e) {  
            Log.wtf("HookDetection", e.toString());  
        }  
        return false;  
    }  
 

3.查詢程式執行的棧中是否存在hook相關類

private static boolean findHookStack() {  
        try {  
            throw new Exception("findhook");  
        } catch (Exception e) {  
  
            // 讀取棧資訊  
            // for(StackTraceElement stackTraceElement : e.getStackTrace()) {  
            // Log.wtf("HookDetection", stackTraceElement.getClassName() + "->"+  
            // stackTraceElement.getMethodName());  
            // }  
  
            int zygoteInitCallCount = 0;  
            for (StackTraceElement stackTraceElement : e.getStackTrace()) {  
                if (stackTraceElement.getClassName().equals("com.android.internal.os.ZygoteInit")) {  
                    zygoteInitCallCount++;  
                    if (zygoteInitCallCount == 2) {  
                        Log.wtf("HookDetection", "Substrate is active on the device.");  
                        return true;  
                    }  
                }  
                if (stackTraceElement.getClassName().equals("com.saurik.substrate.MS$2")  
                        && stackTraceElement.getMethodName().equals("invoked")) {  
                    Log.wtf("HookDetection", "A method on the stack trace has been hooked using Substrate.");  
                    return true;  
                }  
                if (stackTraceElement.getClassName().equals("de.robv.android.xposed.XposedBridge")  
                        && stackTraceElement.getMethodName().equals("main")) {  
                    Log.wtf("HookDetection", "Xposed is active on the device.");  
                    return true;  
                }  
                if (stackTraceElement.getClassName().equals("de.robv.android.xposed.XposedBridge")  
                        && stackTraceElement.getMethodName().equals("handleHookedMethod")) {  
                    Log.wtf("HookDetection", "A method on the stack trace has been hooked using Xposed.");  
                    return true;  
                }  
            }  
        }  
        return false;  
    }  
 

4.綜合判斷 （true為hook）

    public static boolean isHook(Context context) {  
        if (findHookAppName(context) || findHookAppFile() || findHookStack()) {  
            return true;  
        }  
        return false;  
    }